• Reproductive and Developmental Biology
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• v.30 no.3
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• pp.219-224
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• 2006

The objective of this study was to investigate the toxic effects of Bisphenol A(BPA) and di-2 ethyhexyl phthalate (DEHP) as endocrine disrupters on sperm motility, viability, membrane integrity and abnormality during in vitro incubation of boar semen. Semen were randomly divide into 24 groups and healed with different concentrations of BPA md DEHP($1{\sim}100{\mu}M$) for 3, 6 and 9 hrs, respectively. The percentages of sperm motility and viability decreased by treatment time with both BPA and DEHP, and obiously differ from the controls. The percentages of sperm motility and viability significantly decreased by incubation with both $100{\mu}M$ of BPA and DEHP compared to control and other treatment groups(p<0.05). Sperm membrane integrity was significantly reduced by incubation with 10 and $100{\mu}M$ of BPA and DEHP, respectively(p<0.05), but sperm abnormality were not significantly affect both BPA and DEHP. These results indicate that high concentration of BPA and DEHP($>10{\mu}M$ can affect noxiously the sperm characteristics.

• Journal of Nutrition and Health
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• v.44 no.1
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• pp.61-73
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• 2011

The aim of this study was to develop a reliable dietary questionnaire to assess human exposure to food-borne hazards. Eleven food-borne hazards were chosen as a priority control list through a literature review and advisory committees. The 11 food-borne hazards were phthalate, aflatoxin, bisphenol A, polycyclic aromatic hydrocarbons, dioxin, polychlorinated biphenyls, mercury, lead, cadmium, arsenic, and acrylamide. The characteristics, exposure level, and paths of these hazards were reviewed, and questionnaire items were identified to assess human exposure from the literature. A questionnaire was developed for each selected food based on its characteristics. Based on the items in the individual questionnaires, a comprehensive questionnaire, which contained demographic characteristics, job information, socioeconomic factors, health related lifestyles, and dietary behaviors, was developed. A 99-item food frequency questionnaire (FFQ) to assess food-borne hazard exposure was also developed. The FFQ included frequency of food intake during the previous year, container type for purchasing and storing food, and cooking method. The questionnaire developed in this study could be applied to assess dietary factors during an exposure assessment of food-borne hazards in a large population. A validation study for the questionnaire is needed before applying it to surveys.

• Journal of Food Hygiene and Safety
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• v.20 no.1
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• pp.1-6
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• 2005

To investigate whether there are estrogenic and anti-estrogenic activities in various medicinal herbs and discover prominent chemo-preventive agents, we screened and compared the ethanol extracts of 9 plants through the recombinant yeast assay and MCF-7 human breast cancer cell assay, In recombinant yeast assay, seven medicinal herbs showed estrogenicity, and four extracts showed androgenecity. In MCF-7 proliferation assay, the growth of MCF-7 cells was inhibited by eight extracts before and even after co-treatment with bisphenol A. It is interesting that the extracts of Glycyrrhiza uralensis, Cassia tora, Syringa velutina, Zingiber officinale, Malva verticillata, and Panax ginseng C.A. Meyer exhibited inhibitory effects as phytoestrogens in estrogen-responsive human breast cancer cells. This study suggests that some Korean medicinal herbs might be considered as phytoestrogens and be useful to further analyze those plants which contain the estrogenic effect in order to identify the active principles.

• Journal of Dental Rehabilitation and Applied Science
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• v.33 no.4
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• pp.260-268
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• 2017

Purpose: Manufacturing with AM (Additive manufacturing) technique has many advantages; but, due to insufficient study in the area, it is not being widely used in the general clinic. In this study, differences of flexural strength among various materials of 3 unit fixed dental prosthesis were analyzed. Materials and Methods: A metal jig for specimens that had a 3-unit-fixed dental prosthesis figure were fabricated. The jigs were made appropriately to the specifications of the specimens. Three different kinds of materials of specimens which were NC (mathacrylic esther based), DP-1 (Bisphenol A epoxy acrylate type oligomer based), and DT-1 (urethane acrylate based) were printed with DLP machine. Five specimens for each kind of material were printed with an angle of $30^{\circ}$ from the horizontal surface. The specimens were placed on the jig and the flexural strength was measured and recorded using Universal testing machine. The recorded data was analyzed in SPSS using One-way ANOVA and Tukey HSD to determine the significance of the differences of flexural strength among the groups. Results: The flexural strengths of each group were the followings: NC, $1119{\pm}305$ N; DP-1, $619{\pm}150$ N; DT-1, $413{\pm}65N$. Using One-way ANOVA and Tukey Honestly Significant Difference test, significant difference was found between NC and the other groups (P < 0.05), but there was no significant difference between DP-1 and DT-1 (P > 0.05). Conclusion: Higher flexural strength was shown in 3-unit-fixed dental prosthesis that were 3D printed using a DLP machine with NC material.

• 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.

• Clean Technology
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• v.21 no.1
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• pp.76-82
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• 2015

Volatile organic compounds (VOC) free adhesives have been interested by many scientists and engineers due to environmental regulations and the safety of industrial workers. In this work, a series of composites composed with bisphenol A epoxy resin used as solvent, dicyandiamide, and promoter were prepared to investigate the most appropriate molar ratio for steel-steel adhesion. The cured test specimen of each composite were measured with universal testing machine (UTM) to figure out mechanical properties such as tensile strength, Young’s modulus, and elongation. Furthermore, the lap shear strength of the specimen was tested with UTM while impact resistance was measured with Izod impact tester. The composite whose molar ratio of epoxy resin to curing agent is 1 : 0.9 (sample 3), showed better tensile strength, coefficient of elastic modulus, elongation, and impact strength than other composites did. The highest tanδ from dynamic mechanical analysis (DMA) was observed from sample 2 (epoxy resin: dicy = 1 : 0.7) while sample 3 showed slightly lower tanδ than that of 2. The morphology of the fracture surface of the cured composites from SEM showed that the number of subtle lines on the surface caused by impact increase as the contents of amine curing agent accrete. Furthermore, the viscosity change of sample 5 (epoxy resin: dicy = 1 : 1.3) was observed to confirm its storage stability.

• Journal of Animal Science and Technology
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• v.46 no.6
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• pp.957-966
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• 2004

The objective of this study was to investigate the effects of BPA on reproductive characteristic and blood hematological and chemical values in mice. The male mice were intraperitoneally injected BPA in native control(no treatment), positive control(corn oil, 3$m\ell$/kg B.W), 0.05, 0.5 and 5.0mg BPA/kg B.W and female mice were injected BPA in control(corn oil, 3$m\ell$/kg B.W), 0.05, 0.5 and 5.0mg BPA/kg B.W with 5 times at 3 days interval for 14 days. The administration of BPA in male mice didn't affect the body and reproductive organ weight such as testis, epididymis, vesicular gland and coagulating gland. We found that the 5.0mg BPA group was significantly reduced the sperm concentration and increased the sperm abnormality compared to native, positive control and 0.05mg BPA groups(P<0.05), but any other effects were not found in sperm viability and motility in BPA treatment groups. The RBC, HB, HT, MCV, MCH, MCHC, albumin, BUN and total protein of blood hematological and chemical values in male were not different in all experimental groups(P>0.05). However, the value of WBC was slightly lower in BPA treatment groups than that of control groups and PLT was slightly higher in BPA groups than that of control groups, but not significantly defference among the experimental groups(P>0.05). In female mice, the effects of BPA on body weight didn’t affect in all experimental groups, but ovary weights in 0.5 and 5.0mg BPA groups were significantly increased compared to those in control and 0.05mg BPA group(P<0.05). The uterine weight in BPA groups was slightly higher than that of control group, but not significantly different in all experimental groups(P>0.05). The RBC, Hb, HT, MCV, MCH, MCHC, albumin and total protein of blood hematological and chemical values in female were not different in all experimental groups(P>0.05). The values of WBC and PLT in BPA groups were slightly higher than that of control, but not significantly different among the experimental groups. The concentration of BUN was the higher in BPA groups than that of control group. The histological evaluation of testis, ovary and uterus were not different in all experimental groups.

• Journal of Food Hygiene and Safety
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• v.21 no.2
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• pp.100-106
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• 2006

The use of underarm and body care cosmetics with oestrogenic chemical excipients (particularly the parabens) and the hypothesized association with breast cancer incidence, particularly in women. It is noted that the type of cosmetic product is irrelevant (e.g. antiperspirant/deodorant versus body lotion, moisturizers or sprays versus creams) and attention must focus on issues of actual exposure to chemicals through continued dermal application of body care products and the endocrine/hormonal activity and toxicity of the chemicals in the formulations. To evaluate the estrogenic activities of parabens such as ethylparaben, butylparaben, propylparaben, isobutylparaben and isopropylparaben, we used recombinant yeasts containing the human estrogen receptor [Saccharomyces cerevisiae ER+LYS 8127], human breast cancer MCF-7 cell lines and human estrogen receptor ${\alpha}\;and\;{\beta}$. In E-screen assays, isopropylparaben is the most estrogenic paraben, and in ER competition assay, isobutylparaben is the most estrogenic paraben. We evaluated isopropylparaben was most active in the recombinant yeast assay, followed by propylparaben, ethylparaben, isobutylparaben and butylparaben. Results from this study demonstrate that parabens are observed in human endocrine system. Therefore, we have shown that the parabens is induced the estrogenic activities similar to $17{\beta}$-estradiol and Bisphenol-A.