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        검색결과 13

        4.
        2020.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Dentin hypersensitivity (DH) is defined as short and sharp pain caused by external stimuli such as heat, vaporization, contact, osmotic pressure, and chemical stimulation in a normal tooth, rather than due to disease or tooth damage. Its solution is to block the flow of dentinal fluid by physically blocking the dentinal tubule. Of these treatments, fluoride and oxalate type for hypersensitivity can only have a temporary effect. Resins should be used with a suitable bonding system and they may cause hypersensitivity symptoms after treatment. Overcoming these limitations, there is a need for method that can effectively treat dental hypersensitivity lasting long without any side effects. For this reason, experiments with 200 plant extracts as candidates for dentin hypersensitivity, Buddleja officinalis was considered as a candidate for present study. The purpose of this study is to confirm whether the ethanol extract of Buddleja officinalis is effective to protect enamel and dentin by coating tooth surface and resistance to acid or alkali even after tooth coating.
        4,000원
        5.
        2018.10 구독 인증기관·개인회원 무료
        The spotted wing drosophila(Drosophila suzukii)is one of the serious fruit pest that has a wide range of fruit crops like blueberries, cherries and grapes. It came up the larvae cause dagmage by feeding on the pulp inside fruits and berries and spotted wing drosophila also has a adversely affect export to Austrailia and New zealand as a quarantine pest. This study conduct to survey occurrence of drosophila spp. from 2016 to 2018 on harvest period of grapevine in vinyard of Okcheon ,Yeongdong and fruit packing place for export to New zealand and USA. Vinegar and wine mixture was used to attract fruits flies. We also investigated to what color is the best stimulus to catch a vinegar flies. Our result shows that significant differences were observed in total flies trapped in red and black colors. This study will contribute to future research for monitoring and control drosophilid flies.
        6.
        2018.05 구독 인증기관·개인회원 무료
        In this study, several approaches in evaluating moisture sensitivity of asphalt mixtures were investigated and compared. To evaluate the moisture damage resistance, twenty types of asphalt mixtures with and without anti stripping additives were tested in the laboratory. Uniaxial compressive strength (UCS) and indirect tensile (IDT) testing were performed to determine the Tensile Strength Ratio (TSR) and Cohesion Strength Ratio (CSR). Stone Mastic Asphalt (SMA) mixtures were found to provide good moisture damage resistance compared to other mixtures. It also does not require anti stripping additives to improve its moisture resistance. Moreover, the correlation coefficient between the TSR test and CSR tests is 0.99 with an average error of 1.5%, which indicates that the TSR test following AASHTO T-283 is still the most reasonable criteria in evaluating the moisture damage of AC mixtures. Marshall Stability Ratio (MSR) and Marshall Stability to Flow Ratio (MSFR) were conducted and were compared to TSR test results. It was found that MSFR value may be used to evaluate the moisture damage resistance of AC mixtures instead of TSR test. Finally, Dynamic Immersion (DI) test was performed to evaluate moisture resistance for loose asphalt mixtures. The DI results showed good correlation also when evaluating moisture resistance compared to TSR. When using DI testing in evaluating moisture resistance, it is recommended to test after 48 hours since it showed higher correlation with the TSR values. Further study is recommended to improve current testing evaluating moisture susceptibility of asphalt mixtures to properly associate it with TSR values.
        7.
        2017.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES:The objective of this study is to evaluate the performance of asphalt mixtures containing inorganic additive and a high content of reclaimed asphalt pavement (RAP).METHODS:The laboratory tests verified the superior laboratory performance of inorganic additive compared to cement, in cold recycled asphalt mixtures. To investigate the moisture susceptibility of the specimens, tensile strength ratio (TSR) tests were performed. In addition, dynamic modulus test was conducted to evaluate the performance of cold recycled asphalt mixture.RESULTS:It was determined that NaOH solution mixed with Na2SiO3 in the ratio 75:10 provides optimum performance. Compared to Type B and C counterparts, Type A mixtures consisting of an inorganic additive performed better in the Indirect tensile strength test, tensile strength ratio test, and dynamic modulus test.CONCLUSIONS:The use of inorganic additive enhances the indirect strength and dynamic modulus performance of the asphalt mixture. However, additional experiments are to be conducted to improve the reliability of the result with respect to the effect of inorganic additive.
        4,000원
        8.
        2017.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES:The objective of this study is to evaluate the effect of anti-stripping on asphalt mixtures constituting anti-stripping agents.METHODS:Based on the literature review, asphalt mixture added with anti-stripping agents was prepared, and these asphalt mixtures were evaluated for anti-stripping properties for each anti-stripping agent through various lab tests, namely, tensile strength ratio (TSR), dynamic immersion test, uniaxial compression test, and indirect tensile strength test (IDT). The liquid anti-stripping agents used in the lab test were premixed with each asphalt binder (PG 64-22, PG 76-22) before being mixed with the aggregate.RESULTS:The result of the TSR test revealed that the effect of anti-stripping was highest when hydrated lime and liquid anti-stripping agent W were added. The correlation coefficient R2 between the TSR result and cohesion ratio is 0.99, which indicates that the sensitivity of the TSR to moisture damage is reliable from the mechanical point of view. The covering ratio of the asphalt binder to the liquid anti-stripping agent W was determined to be higher than that to the other liquid anti-stripping agents.CONCLUSIONS:It is considered that the improved moisture resistance of asphalt mixture as a result of the use of anti-stripping agents can reduce the incidence of various pavement damages such as portholes caused by stripping, and the performance life of the asphalt road pavement can be prolonged.
        4,000원
        9.
        2010.05 구독 인증기관·개인회원 무료
        The silkworm (Bombyx mori), as an industrial insect, possesses a high economic value. Casual discrimination and accumulated genetic information of silkworm varieties are essential ground for the practical utilization and long-term conservation. In this study, nine available microsatellite loci were successfully genotyped from ~50 silkworm strains preserved in Korea. According to genotyping analysis, we obtained 3 ~ 16 alleles per locus, with an average of 7.4, the observed heterozygosity ranging from 0.04 to 0.98, and the polymorphic information content (PIC) ranging from 0.06 to 0.88, revealing that some loci are highly variable. Among 54 strains 13 strains were casually identified by the presence of 17 strain-specific apomorphic alleles. Furthermore, 30 among remaining strains contained strain-specific allele combinations that are also apomorphic to each strain, allowing us to discriminate each of these from other strains by genotyping of multiple loci. These results collectively suggest that the silkworm microsatellite DNA is actually and potentially important molecular marker for the discrimination of the silkworm strains that are preserved as hundreds in Korea, as more loci are genotyped.
        10.
        2007.10 KCI 등재 구독 인증기관·개인회원 무료
        Mammalian Emx2. a homeobox tra nscripti on factor‘ is continuoll s ly expressecl in aclll lt neural s tem cell s of the b.ippo campal c1enclate gyrus (HDG) a f'ter blrth 1'0 c1ate‘ roles 01' Emx2 a ncl its llnderlying rnecha ni s rn in r eg비 atin g acl lllt neuro - genesis from neural stem cell aft er bi rth is still obscure. 1'he present experiment is aimed to elucidate role 01' Emx2 in regulating adll lt neurogenesis from neural s tem cell of HDG using nestin-Emx2 transgenic mouse (N-E2 1'G) and heterozygous Emx2 KO mouse (1-l-E2 KO) . HDG g ranlllar cell layer where new born neurons proclllced from adult neural stem cell migrate. is thin with low cell c1ens ity in N-E2 1'G but tbick with high cell density in H-E2 KO, compared to wild type mice (\\끼') . Number of DCX , a new born nellron marker. -positive cells is less in N-E2 1'G but more in l-l-E2 KO. comparecl to W1'. Ki67 (whole cell cycle marker) 01' BrclU (S-phase marker) 一positive cells is less in N-E2 1'G bllt morc in l-l-E2 KO and BrdU-positive cells/ Ki 67ratio is higher in N-E2 1'G but lower in H-E2 KO. NeuN (a mature n e llro삐 marker) a ncl BrdU-dollble positive cells is lUore in N- E2 TG bllt GFAP (a glial cell marker) ancl BrdU- dollble positive cells is more in ]-]- E2 KO. compa recl to WT 4wks after BrclU is aclmin istratecl one ti me per c1ay for 5days‘ Migrating c1egree of BrdU-positive cells is lower in N-E2 TG but higher in ]-]-E2 KO 4wks after BrclU is administratecl one t ime per day for 5days. Active casepase 3-positive cells is more in ]-]DG 01' the N-E2 TG but no changes in ]-]-E2 KO. 4 wks after CAG- GFP- PRE vector was inj ected in hippocampus. GFP-positive new born n e urons from aclult neural stem cell have less c1endritic branches in N-E2 1'G but more c1endritic branches in H-E2 KO‘ comparecl to the WT From these results. Emx2 transcription factor inhibits adult neurogenesis f'rom nellral stem cell of HDG throllgh reducing neural stem cell proliferation. new born cell survival. ce ll migration. ancl matllrat ion