• Archives of Plastic Surgery
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• v.34 no.3
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• pp.298-304
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• 2007

Purpose: This study was undertaken to investigate the osteogenic induction potential of PGA & FBS mixture on a calvarial defect in the rabbit. Methods: Twenty New zealand white rabbit, weighing from 3.5-4kg were allocated into each of the three groups. Four 8 mm sized bone defects were made on the parietal bone by drilling. In group I, the bony defects were implanted with $50{\mu}m$ thickness film containing mixture of PGA and FBS. In group II, with PGA only film, & in group III, the bony defects were left with no implants. Results were evaluated by using morphologic change, radiographic study, biochemical study and histologic examination at 1 week (group I n=7, group II n=7, group III n=14), 2 weeks (group I n=6, group II n=6, group III n=12) and 3 weeks (group I n=7, group II n=7, group III n=14) following implantation. Results: In the morphologic & radiographic study, the formation and corticalization of callus were observed earlier in group I than in groups II and III (p < 0.05). In histological examination, group I showed more abundant and faster new bone formation than in group II and III. In biochemical analysis, group I displayed more activity than in group II and III. Group I also showed more abundant osteopontin, osteocalcin than groups II and III. Conclusion: In conclusion, the results demonstrate that the mixture of PGA and FBS has an effect on osteoblastic formation in the rabbit model. It is considered that further evaluation of long term results on resorption, immunologic tissue reaction and response of applied mixture in the human model will be needed.

• Korean Journal of Poultry Science
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• v.32 no.3
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• pp.219-224
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• 2005

This study was carried out to investigate the effect of feldspar on laying Performance and e99 qualify in hens. A total of 96 'Tetra Brown' layers were assigned to 4 treatments in a completely randomized design. Each treatment consisted 4 replicates accommodating 6 layers per replication. Experiment diets were a control diet without feldspar and supplemented 0.5, 1.0 and $1.5\%$ feldspar. The egg Production rate was significantly increased in layers 134 diets supplemented 0.5 and $1.0\%$ feldspar compared to that of control (P<0.05). Egg weight, egg mass, feed intake, feed conversion ratio, egg shell strength and egg yolk color were not significantly different among the treatments (P>0.05). The haugh unit and blood spot of the eggs were significantly increased in $1.5\%$ feldspa. diets compared to that of control (p<0.05). However, the albumen index and meat spot in the eggs were not statistically different among treatments (P>0.05). Sensory evaluation traits were not significantly differed in terms of appearance, color, texture flavor and overall acceptability of eggs (P>0.05). The juiciness of boiled eggs was significantly increased in eggs of birds fed $1.0\%$ feldspar diets(P>0.05).

• Journal of the Korean Society of Radiology
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• v.14 no.2
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• pp.149-155
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• 2020

Most of radiation protection clothing is made of lead with excellent radiation shielding because it has excellent process ability and economic efficiency and has a high atomic number. However, lead is classified as a hazardous heavy metal, and there is a risk of lead poisoning. Recently, research to replace lead has been actively conducted. In this study, a research on a shielding sheet with improved physical properties while maintaining the radiation shielding ability equivalent to that of conventional materials by mixing two materials that are harmless to the human body, such as BaSO₄ and Bi₂O₃, and a silicone material binder Was performed. For comparison evaluation with the existing lead shielding sheet, the shielding rate was evaluated using a 40 degree shielding sheet having the highest porosity. As a result, it was analyzed that the shielding rate was superior to 9 % or more at the same thickness. In addition, as a result of studies to improve the physical properties of the shielding sheet, it was analyzed that the shielding sheet mixed with BaSO₄/nylon/Bi₂O₃ was the best.

• Toxicological Research
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• v.33 no.3
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• pp.255-263
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• 2017

Chemotherapy is associated with male infertility. Cisplatin (cis-diamminedichloro-platinum (II) (CDDP) as a chemotherapy medication used to treat a number of cancers has been reported to most likely induce testicular toxicity. Administration of antioxidants, such as pentoxifylline (PTX) may reduce some Adverse Drug Reactions (ADRs) of CDDP. Therefore, this study investigated the potentially protective effects of PTX on CDDP-induced testicular toxicity in adult male rats. For this purpose, 42 male rats were randomly divided into 7 groups. The rats were orally pretreated with PTX at the 3 doses of 75, 150, and 300 mg/kg once a day for 14 successive days. On the $14^{th}$ day of the study, they were intraperitoneally (IP) administered with a single dose of CDDP (7 mg/kg). Finally, the sperm/testis parameters, serum levels of reproductive hormones, including testosterone, Luteinizing Hormone (LH), and Follicle Stimulating Hormone (FSH) as the pivotal endocrine factors controlling testicular functions, and histopathological changes of testis tissue were examined. Pretreatment with the two doses of 75 and 150 mg/kg PTX indicated significant increases in the sperm count and motility induced by CDDP administration. The right and significantly left testis weights were decreased following the treatment with 300 mg/kg of PTX plus CDDP. However, 75 mg/kg of PTX plus CDDP showed the best near-to-normal histopathological features. The results demonstrated that PTX alone enhanced some parameters, such as the sperm count, while reducing other parameters, including sperm fast motility and germ layer thickness. Furthermore, despite testosterone or LH levels, the mean serum FSH level was significantly augmented by the doses of 75 and 150 mg/kg. It was concluded that PTX administration cannot reduce CDDP-induced testicular toxicity even at high doses (e.g., 300 mg/kg), while it seemed to partially intensify CDDP toxicity effects at a dose of 75 mg/kg. Thus, further research is required in this regard.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06b
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• pp.231-237
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• 2006

Grease barrier food containers are commonly used for packaging of fast food, cooked food, and food in general. Greaseproofing is also used for certificate paper and label paper etc. Different pulp raw materials, due to their different fiber morphology and chemical compositions, produce papers of varying characteristics. We used optical photomicroscopy and fiber analysis data to evaluate fiber morphology and traits under various beating conditions in order to understand which pulp raw materials produced superior greaseproofing property when a fluorinated greaseproofing agent was added internally. The experiment studied 9 species of pulps, including 2 softwood (northern pine and radiata pine) bleached kraft pulps which were beaten to 550 and 350 mL CSF, respectively; 3 hardwoods (eucalypts, acacia, mixed Indonesian hardwoods) bleached kraft pulps which were beaten to 450 and 250 mL CSF, respectively; and nonwood fibers of reed, bagasse, and abaca. A fluorinated greaseproofing chemical at 0.12% dosage with respect to dry pulp was added to each pulp preparation and formed handsheets. A total of 67 sets of handsheets were prepared, and their basis weights, thickness, bulks, opacities, wet opacities, air resistance, water absorption and degrees of greaseproofing were measured for an overall evaluation of pulp and freeness on greaseproofing papers. The experimental fiber length, coarseness and distribution characteristics and the greaseproofing results suggest that softwood pulps (radiate pine > northern pine) were superior to hardwood pulps (eucalypts > acacia > mixed Indonesian hardwoods). The unbeaten pulps gave papers with high porosities and nearly devoid of greaseproofing property. Greaseproofing is proportional to air resistance. Among the nonwood fibers, bagasse had the best greaseproofing property, followed by reed and abaca was the poorest. With regards to waterproofing property, hardwood pulps (mixed Indonesian hardwoods > acacia > eucalypts) were better than softwood pulps (northern pine > radiate pine). Among the Nonwood fibers, reed had the highest waterproofing property, and it was followed by abaca, while bagasse had the poorest waterproofing characteristic. In summary, bleached kraft northern pine, eucalypts and reed pulps were best suited for making greaseproofing papers, Freeness of the pulps should be kept at $200{\sim}280mL$ CSF for optimal performance.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.7
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• pp.635-643
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• 2017

The purpose of this study is to investigate the influence of the cold reduction rate and an ultrasonic fatigue test (UFT) on the fatigue behaviors of STS 304L. The tensile strength, yield strength, hardness value and fatigue limit in the UFT fatigue test linearly increased as thickness decreased from 1.5 mm to 1.1 mm, as the cold reduction rate of STS 304L increased. As a result of the UFT fatigue test (R = -1) of four specimens, the fatigue limit of the S-N curve formed a knee point in the region of $10^6$, and the 2nd fatigue limit caused by giga cycle fatigue did not appeared. In the case of t = 1.1 mm, the highest fatigue limit was 345 MPa, which was 64.3% higher than the original material (t = 1.5 mm). As a result of the UFT fatigue test of STS 304L, many small surface cracks occurred, grown, coalesced while tearing.

• Journal of The Korean Society of Grassland and Forage Science
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• v.32 no.2
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• pp.175-184
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• 2012

In the present study, the effects of feeding different forage sources on the growth performance, meat production and meat quality of Hanwoo steers were evaluated using meta-analysis. In total 5 studies that were performed and published in the domestic journals in Korea were employed for the analysis. The results from nutritionally better quality roughage-based steers and rice straw-based steers in each study were assigned as a treatment and a control, respectively, and the mean difference between the treatment and the control was used for the evaluation of effect size. The summary effect was calculated using random effect model. As results, in growth performance, positive effects were found in feed intake, daily weight gain, final body weight and feed efficiency. The significant effect was found only in daily weight gain (p<0.05). In meat production, carcass weight, Longissimus dorsi area, yield index showed positive effect and negative effect was detected in back fat thickness. The significant effect in meat production was found in carcass weight and Longissimus dorsi area (p<0.05). In meat quality, positive effects were represented in marbling score and fat color. Meat color showed little effect. The significance for effects was not observed in the analysis of meat quality. In conclusion, feeding good quality forages to ruminants plays an important role in Korean beef cattle industry and hence further researches are necessary to improve the efficiency of forage utilization in Hanwoo cattle.

• International Journal of Highway Engineering
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• v.7 no.3 s.25
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• pp.1-10
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• 2005

In this study, accelerated pavement tester(APT) was performed on long-life asphalt pavements that can save maintenance and user costs by increasing the design life twice longer than conventional asphalt pavements. Basic material testings are first conducted on a high modulus base(HMB) mixture developed in this study. Four different pavement sections including thin and thick conventional and thin and thick HMB courses are constructed to compare the load-carrying capacities and to investigate the fatigue and rutting performances using an accelerated pavement tester. Tensile strain values at the bottom of base courses under the various loading levels are measured. The tensile strain values of the HMB sections are lower than those of the conventional sections. It is observed from the APT performed on the thin pavement sections that no significant cracks are developed up to the 180,000 cycles of a wheel load. In terms of rutting, only 3mm of rutting is developed in the thick HMB section while 5.3mm of rutting is developed in the thick conventional section at the 90,000 cycles of the wheel load. The HMB material developed in this study can be successfully used in the long-life asphalt pavements because of its excellent fatigue and rutting performances. It is estimated from a series of structural analysis that the use of the HMB material instead of the conventional base materials may reduce the asphalt thickness at least 5cm because of its better load-carrying capacity.

• International Journal of Highway Engineering
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• v.12 no.2
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• pp.99-106
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• 2010

Until now, the thickness design of anti-freezing layer has been empirically conducted using the frost depth determined from the freezing index. This approach cannot consider the structural properties of anti-freezing layer, which can cause the over-design of pavement structure. This paper presents results of structural evaluation of anti-freezing layer using the Falling Weight Deflectormeter (FWD) deflections. The FWD testing was directly conducted on top of the subbase layer located at the embankment, cutting, and boundary area of each section. It is observed from this testing that the center deflections of pavement structure with anti-freezing layer are smaller than those without anti-freezing layer. The deflection reduction rates are 15~55% in the embankment, 11~64% in the cutting, and 2~38% in the boundary, respectively. It was also found that the use of antifree zing layer enables to reduce the Surface Curvature Index (SCI) values up to 24 percent. Fatigue lives show that pavement structure with antifreezing layer are about two times higher than the those without anti-freezing layer. This fact indicates that the anti-freezing layer should be considered as a structural layer in the asphalt pavement system.

• Journal of radiological science and technology
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• v.39 no.3
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• pp.313-321
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• 2016

Placenta accrete patients whose mother mortality rates are rather high due to massive bleeding during childbirth need to have Prophylactic placement of Internal Iliac Artery Balloon Occlusion Catheters procedure to reduce amount of blood loss and inoperative transfusion. Nevertheless, studies for mothers inevitably exposed to dose during PIIABOCs procedure have not been published many yet. Therefore, this study is to investigate exact information on radiation dose exposed to fetus during PIIABOCs procedure. Average effective dose of fetus per organ is 2.38~8.83 mGy, measured highest at beam center and followed by eyeball, stomach and bladder. The result showed that the longer fluoroscopy time is used, the closer beam center is and the thicker abdominal thickness is, the more effective dose on fetus is increasing. When using the collimator and protection shown to decrease the effective dose and when using higher the patient table shown to decrease the effective dose. It has been reported that the threshold of deterministic effect is about 100mGy. Deterministic effect was regarded as a factor that would influence on fetus exposed by medical radiation than stochastic effect. Consequently, it concluded that dose exposed on fetus in PIIABOCs procedure was approximately 10% of threshold of deterministic effect with effective dose of 0.49~18.27 mGy.