• Journal of Technologic Dentistry
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• v.32 no.3
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• pp.195-207
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• 2010

Purpose: The purpose of this study was to observe the microstructural changes of surface in the specimens, performing the shear bond strength testing. The currently most used non-precious alloys are nickel-chromium based alloys with or without beryllium. However, their biocompatibility has been questioned concerning possible damages to the health of the patient and professionals involved in the fabrication of prosthesis caused by long exposure to Ni and Be. An option to nickel-chromium alloys is the cobalt-chromium alloy, an alternative that does not sacrifice the physical properties of the metal porcelain systems. Studies in the animals substantially show that the cobalt-chromium alloys are relatively well tolerated, being therefore more biocompatible than the nickel-chromium alloys. Methods: Non-addition Be to nickel-chromium based alloy(Bellabond plus) and cobalt-chromium alloy which has been widely used(Wirobond C) fused with ZEO light porcelain classified control group and cobalt-chromium alloy which is developing alloy of Alphadent company in Korea(Alphadent alloy) fused with ZEO light porcelain classified experimental group. The specimens of $4mm{\times}4mm{\times}0.5mm$ were prepared as-cast and as-opaque to cast body to analyze the mechanical characteristic change, the microstructure of alloy surface. The phase change was used to observe through XRD analysis and OM/SEM was used to observe the surface of specimens as-cast and as-opaque to cast body. Chemical formation of their elements was measured with EDS. Then hardness was measured with Micro Vicker's hardness tester. Shear bond strength test thirty specimens of $10mm{\times}10mm{\times}2mm$ was prepared, veneered, 3mm high and 3mm in diameter, over the alloy specimens. The shear bond strength test was performed in a universal testing machine(UTM) with a cross head speed of 0.5mm/min. Ultimate shear bond strength data were analyzed with one-way ANOVA and the Scheffe's test (P<0.05). Within the limits of this study, the following conclusions were drawn: The X-ray diffraction analysis results for the as-cast and as-opaque specimens showed that the major relative intensity of Bellabond plus alloy were changed smaller than Wirobond C and Alphadent Co-Cr based alloys. Results: Microstructural analysis results for the opaque specimens showed all the alloys increased carbides and precipitation(PPT). Alphadent Co-Cr based alloy showed the carbides of lamellar type. The Vickers hardness results for the opaque specimens showed Wirobond C and Alphadent Co-Cr based alloys were increaser than before ascast, but Bellabond plus alloy relatively decreased. The mean shear bond strengths (MPa) were: 33.11 for Wirobond C/ZEO light; 25.00 for Alphadent Co-Cr alloy/ZEO light; 18.02 for Bellabond plus/ZEO light. Conclusion: The mean shear bond strengths for Co-Cr and Ni-Cr based alloy were significantly different. But the all groups showed metal-metal oxide modes in shear bond strengths test at the interface.

• Journal of Technologic Dentistry
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• v.30 no.2
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• pp.47-56
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• 2008

This is a research for thickness change of denture base according to the shape of sprue & investment position of denture base in flask when injecting polyamid base resin for flexible partial denture as a part of study for Valplast among the flexible partial denture with a nylon base. It has been introduced several kinds of flexible partial denture product with a nylon base, but Valplast is the most widely used product among them. Valplast has been the most generally used material today since developed in 1950s in the United States as a material for flexible partial denture. Valplast is much more aesthetic than general metal-acrylic partial denture due to its translucent pink color and biocompatibility in terms of material characteristic. It keeps its flexibility for a long time after production, imposes a less burden on the teeth used as abutment, and it can be easily insert and remove due to its particular suppleness. Moreover, it is felt like real teeth more than metal-acrylic partial denture when being put in and takes alveolar bone under good protection since it receives occlusal force equally under the denture base. The most outstanding feature of Valplast is flexibility. The extent of its flexibility is determined by width & thickness of denture base. Considering general working procedure of Valplast, it can be seen that the thickness of denture base formed out of wax is increasing by the pressure while injecting resin. This research is to decide and test on the thickness increasing of Valplast by injecting pressure and the hypothesis upon that and is to prepare the basis estimating the increasing extent of thickness of denture base on the basis of the test result. In this test, it is expected occlusal malposition & thickness increasing of denture base by injecting pressure according to 4 kinds of test data which are to select 3 types of sprue method settling the forefront position at which the test material of fixed standard can be invested and to position the test material at the rearmost part keeping the minimum distance to set sprue. For 4 kinds of injecting test by investment position & sprue type, 20 test materials, 5 for each test were produced and a pressure of 1,180Kg was given with automatic injector of air cylinder type. The results are as follows: 1. For the amount of thickness increasing of denture base by investment position, the thickness of front investment is less increasing than the one of rear investment. 2. For the amount of thickness increasing of denture base by sprue type, the thickness of straight decompression sprue type which can absorb the injecting pressure after injecting polyamide base resin is less increasing than the other sprue types.

• Journal of Nutrition and Health
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• v.35 no.4
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• pp.431-438
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• 2002

This study was performed to investigate the effects of green tea or antioxidant vitamins on lipid peroxidation and antioxidant enzyme system in various regions of rat brain aged 9 and 12 months. Male Sprague-Dawley rats were raised on the experimental diets; 3% green tea powder diet, antioxidant vitamins diet containing the $\beta$-carotene, vitamin C, vitamin E in the level same as in the 3% green tea powder diet, and control diet far 3 weeks. We measured concentrations of malondialdehyde (MDA) and the activities of superoxide dismutase (SOD), catalase, and glutathione peroxide (GSH-Px) in various brain regions such as cortex, cerebellum, striatum, and hippocampus. Green tea powder or antioxidant vitamin supplementation decreased MDA concentrations in the striatum and the hippocampus, and increased SOB activities in the striatum, and GSH-Px activities in the cortex. There was no significant difference in the observed antioxidative effects between the green tea powder and antioxidant vitamin supplementation. A significant difference between 9 month- and 12 month-old rats was found in MDA concentrations and GSH-Px activities in all brain regions. These results suggest that green tea powder can have protective effects on various regions of rat brain and that these effects on lipid peroxidation and antioxidant enzymes are different by age. In inhibiting lipid peroxidation, there was no difference between green tea powder and antioxidant vitamins.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.45 no.6
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• pp.606-611
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• 2012

This study examined the effects of dietary glycoprotein extracted from Porphyra yezoensi on growth performance and resistance against the pathogenic bacteria Edwardsiella tarda in olive flounder. A porphyra-originated glycoprotein (P) was extracted using sequential processes of water and ethanol treatment. P extracts were added to a fish-meal-based diet at concentrations of 0.0, 0.5, and 1.0% (designated as Con, $P_{0.5}$, and $P_{1.0}$, respectively). Fish were fed one of the three experimental diets for 10 weeks. All fish groups exhibited over 96.7% survival during the experimental period. Results indicated that the fish fed diets containing P showed an increase in growth performance, including enhanced weight gain, specific growth rate, and feed efficiency. An increase in insulin-like growth factor (IGF-1) was observed in the fish fed the $P_{1.0}$ diet, as compared to those fed Con. At the end of the 10-week feeding trial, all fish were infected with E. tarda, and accumulated mortality was monitored for 8 days. Fish fed the Con diet exhibited increasing mortality from day 3 to the end of the challenge test, whereas the mortality of P-fed fish ceased at day 5. We suggest that supplementation with P-originated glycoprotein in aquafeed may increase growth performance and resistance against pathogenic bacteria in olive flounder juveniles.

• Fisheries and Aquatic Sciences
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• v.19 no.5
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• pp.24.1-24.6
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• 2016

We determined the optimum dietary protein level in juvenile barred knifejaw Oplegnathus fasciatus in cages. Five semi-purified isocaloric diets were formulated with white fish meal and casein-based diets to contain 35, 40, 45, 50, and 60 % crude protein (CP). Fish with an initial body weight of $7.1{\pm}0.06g$ ($mean{\pm}SD$) were randomly distributed into 15 net cages (each size: $60cm{\times}40cm{\times}90cm$, $W{\times}L{\times}H$) as groups of 20 fish in triplicates. The fish were fed at apparent satiation level twice a day. After 8 weeks of feeding, the weight gain (WG) of fish fed 45, 50, and 60 % CP diets were significantly higher than those of fish fed 35 and 40 % CP diets. However, there were no significant differences in WG among fish fed 45, 50, and 60 % CP diets. Generally, feed efficiency (FE) and specific growth rate (SGR) showed a similar trend as WG. However, the protein efficiency ratio (PER) was inversely related to dietary protein levels. Energy retention efficiency increased with the increase of dietary protein levels by protein sparing from non-protein energy sources. Blood hematocrit content was not affected by dietary protein levels. However, a significantly lower amount of hemoglobin was found in fish fed 35 % CP than in fish fed 40, 45, 50, and 60 % CP diets. Fish fed 60 % CP showed the lowest survival rate than the fish fed 35, 40, 45, and 50 % CP diets. Broken-line analysis of WG showed the optimum dietary protein level was 45.2 % with 18.8 kJ/g diet for juvenile barred knifejaw. This study has potential implication for the successful cage culture of barred knifejaw.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.5
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• pp.490-496
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• 2002

In order to detect the DNA heteropolymorphism of chum salmon, selected essential genes were examined in different regional chum salmons, i.e., Korean, Japanese and American by denaturing gradient gel electrophoresis (DGGE) and real time PCR methods. From the promoter regions and introns of growth hormone, mtDNA NDI region, D-loop region, IGF-I, histone H3 and MCH2 several representative primer pairs were obtained and employed for the DGGE with the PCR products from the genomic DNAs of the different regional chum salmons. mtDNA NDI, D-loop region and IGE-I genes showed marked heteropolymorphism between Korean and American chum salmons. Intron C of growth hormone also showed a heteropolymorphism between Korean and Japanese chum salmons. Whereas heteropolnnorphism of histone liH and MCH2 genes was detected among in Korean, Japanese and Asnerican chum salmons in the examined region. The real time PCR disclosed the characteristic incremental production of target DNAs dependent on the heteropolymorphic conditions of genomic DNAa of chum salmons, thus the different regional chum salmons could be grouped by the variable incremental curies. Although the DGGE and real time PCR did not produce the identical results in this study, we suggest that the DGGE and real time PCR could be used for the primary screening of the DNA heteropolymorphism of different animal genome.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.6
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• pp.1063-1068
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• 2014

We investigated the effects of feeding rate on the growth performance and blood components of sub-adult olive flounder Paralichthys olivaceus. Optimum feeding rate (initial fish mean weight : $370{\pm}5.72g$) was determined under the low water temperature. Two replicated groups of fish were fed a commercial diet at rates of 0%, 0.3%, 0.4%, 0.5%, and 0.6% body weight (BW) per day, and to satiation (0.75%). Feeding trial was conducted under a flow-through system with 12 1.2-metric ton aquaria receiving filtered seawater at $12-14^{\circ}C$ for 4 weeks. Weight gain (WG) and specific growth rate (SGR) for fish fed at 0.6% BW per day was significantly higher than that of unfed fish (0%) and fish fed at 0.3% and 0.4% BW per day. There were no significant differences in WG and SGR among fish fed at 0.5%, 0.6%, and 0.75%. These parameters were negative and significantly lower in the starved fish than in fish fed the experimental diet at all feeding rates. Survival for unfed fish (0%) was significantly lower than that of fish fed at 0.4%, 0.5%, and 0.6%. Hematocrit and hemoglobin content of fish fed at 0% and 0.75% (satiation) were significantly lower than that of fish fed at 0.4% BW per day. Total protein content in unfed fish was significantly lower than those in other treatments. Broken-line regression analysis of weight gain showed that the optimum feeding rate of olive flounder weighing 370 g was 0.51% BW per day at the low water temperature.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.3
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• pp.308-313
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• 2015

A $3{\times}3$ factorial study was conducted to investigate the effects of dietary protein and lipid levels on the growth, feed utilization and innate immunity of red seabream Pagrus major. Nine diets consisting of three protein levels (42%, 46% and 50% crude protein) and three lipid levels (10%, 14% and 18% crude lipid) were formulated. Triplicate groups of red seabream were fed the experimental diets to apparent satiation (5-6 times a day, from 08:00 to 18:00 h at 2-h intervals) for 10 weeks. At the end of the feeding trial, the weight gain and specific growth rate of fish fed P46L14 (46% protein and 14% lipid), P50L10 (50% protein and 10% lipid) and P50L14 (50% protein and 14% lipid) were significantly (P<0.05) higher than those of fish fed P42L18 (42% protein and 18% lipid). The feed conversion ratios (FCR) of the fish were affected by dietary lipid levels (P<0.039), but not dietary protein levels. The FCR tended to increase with increasing dietary lipid levels from 10% to 18% with the 46% and 50% protein levels. The weight gain, protein efficiency ratio, specific growth rate, feed intake and survival of fish were not affected by either dietary protein or lipid levels. Myeloperoxidase activity in the group fed P50L14 (50% protein and 14% lipid) was significantly higher than that in the group fed P42L10 (42% protein and 10% lipid) or P50L18 (50% protein and 18% lipid). However, the myeloperoxidase activity of fish was not affected by either dietary protein or lipid level. The fish fed P46L14 (46% protein and 14% lipid) and P46L18 (46% protein and 18% lipid) showed significantly higher superoxide dismutase activity than did the fish fed P46L10 (46% protein and 10% lipid), P50L10 (50% protein and 10% lipid) of P50L18 (50% protein and 18% lipid). In conclusion, the optimum protein and lipid levels for the growth and feed utilization of juvenile red seabream were 46% and 14%, respectively, and the optimum dietary protein to energy ratio was 27.4 g/MJ.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.6
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• pp.824-831
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• 2014

This study was conducted to investigate the effects of fishmeal replacement with acid-concentrated soybean meal (ACSBM) on growth performance, blood biochemistry, and ingredient digestibility in juvenile olive flounder Paralichthys olivaceus. Six experimental diets were formulated to replace fishmeal protein with ACSBM at 0%, 20%, 30%, 40%, 50%, and 60% (designated ACSBM0, ACSBM20, ACSBM30, ACSBM40, ACSBM50, and ACSBM60, respectively). Triplicate groups of fish (initial fish mean weight: $14.3{\pm}0.03g$) were fed the experimental diets to apparent satiation (twice daily at 08:00 and 18:00 h). After a 12-week feeding trial, a total of 180 healthy fish were randomly distributed into three Guelph system tanks at a density of 60 fish/tank (initial fish mean weight : $50.6{\pm}2.4g$) to test the apparent digestibility coefficients of the ingredients (ACSBM, fishmeal, and soybean meal). Although negative effects were observed with ACSBM40, ACSBM50 and ACSBM60 after 12 weeks of feeding, up to 20% of the fishmeal protein could be successfully replaced with ACSBM without significant growth depression. Hemoglobin and hematocrit values of fish fed the ACSBM50 and ACSBM60 diets were significantly lower than those of fish fed the ACSBM0 diet. Glucose values of fish fed the ACSBM60 diet were significantly higher than those of fish fed the ACSBM0 and ACSBM20 diets. Digestibility of protein in ACSBM and soybean meal was 85.9% and 82.5%, respectively. Results indicated that at least 20% of fishmeal protein can be replaced by ACSBM in diets of juvenile olive flounder without supplementation of limiting amino acids.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.6
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• pp.818-823
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• 2014

This study compared the effects of feeding diets consisting of an experimental extruded pellet with tapioca starch (EEP), commercial extruded pellet (CEP), and raw-fish-based pellet (MP) on the growth, flesh quality, and apparent digestibility coefficient of the olive flounder Paralichthys olivaceus. Two replicated groups of 4,000 fish each (initial mean weight: $81.8{\pm}3.5g$) were fed one of the experimental diets for 5 months. After the feeding trial, the final mean weight, weight gain, specific growth rate, and feed efficiency of fish fed the EEP was significantly higher than those of fish fed the CEP and MP. Moisture content in the whole-body of fish fed MP was significantly higher than those of fish fed other diets. However, the highest crude protein in the whole-body was found in fish groups fed the EEP. Significantly higher contents of 24:1n-9, 20:5n-3, 22:6n-3 and lower 18:1n-7 was observed in fish fed the EEP compared with fish fed the MP. The amino acid contents in the whole-body showed significant differences in the composition depending on the feed, but the distribution of free amino acids showed similar patterns. Among amino acids, glutamic acid showed the highest content in all the experimental groups, and the threonine, cysteine, and lysine contents were significantly higher in the groups fed with EEP and CEP than in the group fed with MP. Digestibility of nutrients of the EEP was significantly higher than that of fish fed the CEP. This suggests that extruded pellets can be used to feed olive flounder without compromising growth and flesh quality in comparison to raw-fish-based moist pellets. Formulation of the EEP could be used as a practical feed for olive flounder.