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        검색결과 312

        101.
        2018.10 구독 인증기관·개인회원 무료
        소나무재선충병의 나무주사는 살선충제를 중심으로 실시되어 왔으며, 매개충인 솔수염하늘소와 북방수염하늘소의 방제는 주로 항공방제나 지상방제를 통하여 이루어졌다. 본 연구에서는 나무주사를 통하여 매개충 (솔수염하늘소)을 방제하기 위한 연구로 Abamectin+Acetamiprid ME, Thiamethoxam DC 약제의 나무주사시 솔수염하늘소의 약효발현농도, 처리 후 기간별 효과(2017년~2018년)를 검토하였다. 실내 발현농도 시험에서는 Acetamiprid, Thiamethoxam LC50 value는 각각 0.102ppm, 0.083ppm 으로 나타 났으며, 야산(포장)에서 Abamectin+Acetamiprid ME, Thiamethoxam DC 처리구의 100.0% 치사 소요일 수는 처리 90일 후 11.0일, 9.4일, 처리 360일 후 11.6일, 10.0일로 나타나서 두 약제 모두 3월 처리시 다음해에 발생하는 매개충 (솔수염하늘소) 방제까지 가능함을 확인 할 수 있었다.
        102.
        2018.10 구독 인증기관·개인회원 무료
        The genus Nipponopsyche Yazaki is reported from Korea with an unrecorded species, N. fuscescens Yazaki for the first time. Adult, larva, pupa and genitalia of the species are redescribed with SEM illustrations, and DNA barcode for precise identification of the species is also provided.
        103.
        2018.10 구독 인증기관·개인회원 무료
        흑백알락나비 (Hestina persimilis (Westwood, 1850))는 한반도의 평안남도 이남의 내륙지역에 넓게 분포하고, 국외의 경우 일본, 중국, 히말라야 일대에 서식하는 것으로 알려져 있다. 본 종에 대한 생활사 연구는 김과 서(2011)에 의해 월동유충, 종령, 번데기 등에 대한 일부 보고가 있을 뿐 자세한 생활사에 대한 기록은 전무하다. 본 연구를 통해 한국산 흑백알락나비의 생태적 습성 및 미성숙단계 (알, 유충, 번데기)의 형태적 특징 등 자세한 생활사 정보를 보고하고자 한다.
        104.
        2018.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        목적: 목적: 최근 근시의 진행을 억제하기 위하여 청소년기 학생들에게 누진렌즈가 처방되고 있다. 그러나 중간 영역의 좁은 시야로 인해 누진렌즈 착용시 영어 및 중국어 문자의 가독성이 저하될 것으로 예상할 수 있다. 이 연구의 목적은 단초점 렌즈를 착용할 때와 누진렌즈를 착용 할 때, 영어와 중국어 문자의 가독성을 비교하는 것이다. 방법: 총 40 명의 피검자가 이 연구에 참여하였다. 피검자들은 누진렌즈 또는 단초점 렌즈를 착용한 상태에서, 영어 또는 중국어 텍스트를 읽을 때 지정된 글자를 찾도록 요구받았다. 주어진 텍스트를 읽는데 걸린 시간을 측정하고, 피검자가 누진렌즈를 착용한 경우와 단초점 렌즈를 착용한 경우를 비교하였다. 텍스트를 읽는데 걸린 시간을 가독성의 기준으로 간주하였다. 결과: 피검자들은 영어와 중국어 문자 양쪽 모두에 대하여, 단초점 렌즈를 착용했을 때보다 누진렌즈를 착용했을 때 텍스트를 읽는데 더 오랜 시간이 걸렸다. 이러한 차이의 통계적 유의성은 영문자 'm'과 중문자 '一'의 경우에 관찰되었다. 결론: 실험 결과로부터, 중간 거리 영역의 좁은 시야로 인하여 누진렌즈의 착용이 가독성을 저하시킨다고 해석할 수 있다. 이러한 가독성의 저하는 청소년 학생들의 학습 능력을 저하시킬 수도 있다는 점을 감안하면, 학습기의 청소년에게 근시 억제를 위한 누진렌즈를 처방할 때 누진렌즈의 협소한 중간거리 시야가 독서 능력을 저하시킬 수 있다는 점을 고려하여 렌즈설계 디자인 등의 측면에서 주의를 기울일 필요가 있다.
        4,000원
        105.
        2018.09 구독 인증기관 무료, 개인회원 유료
        Resveratrol (3,4',5,-trihydroxystilbene), a phytoalexin present in grapes, exerts a variety of actions to reduce superoxides, prevents diabetes mellitus, and inhibits inflammation. Resveratrol acts as a chemo-preventive agent and induces apoptotic cell death in various cancer cells. However, the role of resveratrol in odontoblastic cell differentiation is unclear. In this study, the effect of resveratrol on regulating odontoblast differentiation was examined in MDPC-23 mouse odontoblastic cells derived from mouse dental papilla cells. Resveratrol significantly accelerated mineralization as compared with the control culture in differentiation of MDPC-23 cells. Resveratrol significantly increased expression of ALP mRNA as compared with the control in differentiation of MDPC-23 cells. Resveratrol significantly accelerated expression of ColⅠmRNA as compared with the control in differentiation of MDPC-23 cells. Resveratrol significantly increased expressions of DSPP and DMP-1 mRNAs as compared with the control in differentiation of MDPC-23 cells. Treatment of resveratrol did not significantly affect cell proliferation in MDPC-23 cells. Results suggest resveratrol facilitates odontoblast differentiation and mineralization in differentiation of MDPC-23 cells, and may have potential properties for development and clinical application of dentin regeneration materials.
        4,000원
        106.
        2018.07 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Surfactant-wrapped separation methods of metallic and semiconducting single-walled carbon nanotubes (SWCNTs) can result in large changes in intrinsic physical and chemical properties due to electronic interactions between a nanotube and a surfactant. Our approach to synthesize SWCNTs with an electronic feature relied on utilizing carbon nanorings, [n] cycloparaphenylenes ([n]CPPs), which are the fundamental unit of armchair type SWCNTs (a-SWCNTs) that possess a metallic feature without any surfactants. To obtain long tubular structures from [n]CPPs, the host-guest complexes formed with well-aligned [n]CPP hosts and various fullerene guests on a silicon substrate were pyrolyzed under an ethanol gas flow at a high temperature with focused-ultraviolet laser irradiation. The pyrolyzed [n]CPPs were observed to transform from nanorings to tubular structures with 1.5–1.7 nm diameters corresponding to the employed diameter of [n]CPPs. Our approach suggests that [n]CPPs are useful for structure-controlled synthesis of SWCNTs.
        4,000원
        107.
        2018.06 구독 인증기관 무료, 개인회원 유료
        Oral squamous cell carcinoma (OSCC) is the most common type of oral malignancy. Numerous therapies have been proposed for its cure. Research is continually being conducted to develop new forms of treatment as current therapies are associated with numerous side-effects. Luteolin, a common dietary flavonoid, has been demonstrated to possess strong anti-cancer activity against various human cancer cell lines. Nevertheless, research into luteolin-based anticancer activity against oral cancer remains scarce. Thus, the objective of this study was to assess the effect of luteolin as an anti-cancer agent. After treatment with luteolin, Ca9-22 and CAL-27 oral cancer cells showed condensed nuclei and enhanced apoptotic rate with evidence of mitochondria-mediated apoptosis. Epithelial-mesenchymal transition (EMT) is closely related to tumor migration and invasion. Luteolin suppressed cancer cell invasion and migration in the current study. Elevated expression of E-cadherin, an adherens junction protein, was evident in both cell lines after luteolin treatment. Luteolin also significantly inhibited transcription factors (i.e., N-cadherin, Slug, Snail, Twist, and ZEB-1) that regulated expression of tumor suppressors such as E-cadherin based on Western blot analysis and quantitative PCR. Thus, luteolin could induce mitochondrial apoptosis and inhibit cancer cell invasion and migration by suppressing EMT-induced transcription factors.
        4,000원
        109.
        2018.05 구독 인증기관·개인회원 무료
        This research evaluates the applicability of ponded ash in the production of backfill material. From various ponded ash/sand ratios, cement, and air foam conditions, test specimens were developed to investigate many engineer properties of backfill material. Then, the falling weight deflectometer and excavation tests were carried out to determine the behavior of the material in the actual testbed. The test results suggested that all mixtures achieved optimal flowability performance with acceptable stiffening time. It is indicated that the compressive strength increased as ponded ash and cement contents increased, but the strength decreased with an increase in air-foam content or number of freeze-thaw cycles. From the testbed results, it was found that utilizing 100% ponded ash in the production of backfill material is very promising for sustainable development purpose.
        110.
        2018.05 구독 인증기관·개인회원 무료
        This study evaluated the effect of steel slag and steel wool fibers (SWF) on self-healing performance of asphalt mixture. The microstructure and distribution of SWF in mixture were examined by a computerized tomography scan and image analysis program. Thermal conductivity was investigated using the thermal constant analyser. The heating rate and healing performance were measured by induction heating system. The results showed the uneven distribution and the agglomeration in the mixtures when the content of fibers exceed a certain dosage. It was found that the mix with steel slag had higher heating rate than the mix with normal aggregate; however, its healing performance was slightly lower because of the breaking of weak steel slag. Finally, the mechanical test results indicated that SWF can enhance the resistance and prolong the fatigue life of asphalt mixtures.
        111.
        2018.04 구독 인증기관·개인회원 무료
        The present study evaluated the susceptibility of field populations of Plutella xylostella and Spodoptera exigua larvae to four diamide insecticides—chlorantraniliprole, cyantraniliprole, cyclaniliprole, and flubendiamide. All the four diamide insecticides induced 100% mortality in the populations from Seongju (SJ) and Geochang (GC) when treated at a concentration recommended for P. xylostella. However, a very low insecticidal activity was observed in the population from Pyeongchang (PC) with 42.3% 3 d after treatment with chlorantraniliprole. Further, the populations of S. exigua from Cheongju (CJ), Jindo (JD), and Yeonggwang (YG) were not completely controlled by the 4 diamide insecticides. A comparison of susceptibility of S. exigua larvae to chlorantraniliprole between 2014 and 2017 showed that chlorantraniliprole induced 100% mortality in all populations in 2014, whereas a very low insecticidal activity was observed among the populations in 2017. This study can serve as a basis to control pests effectively using diamide insecticides.
        112.
        2018.04 구독 인증기관·개인회원 무료
        최근 이상기후로 인한 총채벌레 발생 증가와 Neonicotinoids계, Pyrethroids계, Spinosyns계, Avermectins계 약제의 과다 살포, 중복 살포로 인한 저항성 발달로 총채벌레 방제가 어려운 상황이다. 본 연구에서는 총채벌레의 약제저항성 관리 및 효율적인 방제전략을 세우기 위한 기초 연구로 곤충성장저해제(insect growth regulator, IGR)의 적용 가능성을 검토하였다. 꽃노랑총채벌레 알, 1령 약충, 2령 약충, 성충으로 나누어 시험 약제를 처리하고, 조사는 약충의 경우 168시간까지 생충수, 알과 성충은 144시간까지 생충수와 부화 약충수를 조사하였다. 조사결과 클로르플루아주론 유제는 1령 약충, 2령 약충에 대하여 접종 168시간 후 각각 100%, 80%의 방제효과를 나타내었다. 또한 시험약제를 성충에 처리 시 산란에 대한 영향도 확인할 수 있었다. 본 연구결과를 통해 곤충성장저해제의 꽃노랑총채벌레 령기별 적용 가능성을 확인할 수 있었으며, 총채벌레 적용약제의 계통을 다양화하여 저항성 관리에도 도움이 될 수 있다고 판단된다.
        113.
        2018.04 구독 인증기관·개인회원 무료
        The susceptibility of the Frankliniella occidentalis and Frankliniella intonsa was evaluated using 46 commercial insecticides. There were 10 kinds of insecticides as benfuracarb, chlorfenapyr, spinetoram, spinosad, abamectin + chlorfenapyr, abamectin + emamectin benzoate, chlorfenapyr + clothianidin, chlorfenapyr + imidacloprid, clothianidin + spinetoram and dinotefuran + spinetoram, which showed more than 90% mortality against both thrips, F. occidentalis and F. intonsa. Since the F. intonsa is more susceptible than F. occidentalis, it is considered that both thrips can be controlled by insecticides that show insecticidal activity on the F. occidentalis. The effect by the elapsed time after treatment of 10 kinds of insecticides was analyzed as LT50 and LT95 values. Benfuracarb was the fastest in 4.3 h (LT50) and 14 h (LT95), and spinetoram showed the most late time at 13.5 h (LT50) and 62.3 h (LT95), respectively.
        114.
        2017.12 구독 인증기관 무료, 개인회원 유료
        The aim of this study was to evaluate the role of demineralized and particulate autogenous tooth, and interleukin-6 in bone regeneration. A demineralized and particulate autogenous tooth was prepared and human osteoblast-like cells (MG63) and human osteosarcoma cells were inoculated into the culture. The rate of cell adhesion, proliferation and mineralization were examined, and the appearance of cellular attachment was observed. An 8 mm critical size defect was created in the cranium of rabbits. Nine rabbits were divided into three groups including: An experimental group A (3 rabbits), in which a demineralised and particulate autogenous tooth was grafted; an experimental group B (3 rabbits), in which a demineralized, particulate autogenous tooth was grafted in addition to interleukin-6 (20 ng/mL); and a control group. The rabbits were sacrificed at 1, 2, 4 and 6 weeks for histopathological examination with H-E and Masson’s Trichrome, and immunohistochemistry with osteocalcin. The cell-based assay showed a higher rate of cell adhesion, mineralization and cellular attachment in the experimental group A compared with the control group. The animal study revealed an increased number of osteoclasts, newly formed and mature bones in the experimental group A compared with the control group. Eventually, a higher number of osteoclasts were observed in the experimental group B. However, the emergence of newly formed and mature bone was lower than in the experimental group A. The current results suggest that treatment with demineralized and particulate autogenous tooth and interleukin-6 is not effective in stimulating bone regeneration during the bone grafting procedure.
        4,000원
        115.
        2017.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We present a study of the inexplicit connection between radio jet activity and γ-ray emission of BL Lacertae (BL Lac; 2200+420). We analyze the long-term millimeter activity of BL Lac via interferometric observations with the Korean VLBI Network (KVN) obtained at 22, 43, 86, and 129 GHz simultaneously over three years (from January 2013 to March 2016); during this time, two γ-ray outbursts (in November 2013 and March 2015) can be seen in γ-ray light curves obtained from Fermi observations. The KVN radio core is optically thick at least up to 86 GHz; there is indication that it might be optically thin at higher frequencies. To first order, the radio light curves decay exponentially over the time span covered by our observations, with decay timescales of 41185 days, 352±79 days, 310±57 days, and 283±55 days at 22, 43, 86, and 129 GHz, respectively. Assuming synchrotron cooling, a cooling time of around one year is consistent with magnetic field strengths B ∼ 2 μT and electron Lorentz factors γ ∼ 10 000. Taking into account that our formal measurement errors include intrinsic variability and thus over-estimate the statistical uncertainties, we nd that the decay timescale  scales with frequency τ ν - 0.2. This relation is much shallower than the one expected from opacity effects (core shift), but in agreement with the (sub-)mm radio core being a standing recollimation shock. We do not find convincing radio flux counterparts to the γ-ray outbursts. The spectral evolution is consistent with the `generalized shock model' of Valtaoja et al. (1992). A temporary increase in the core opacity and the emergence of a knot around the time of the second -ray event indicate that this γ-ray outburst might be an `orphan' are powered by the `ring of fi re' mechanism.
        4,300원
        116.
        2017.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The electronic and optical characteristics of molybdenum disulphide (MoS2) film significantly vary with its thickness, and thus a rapid and accurate estimation of the number of MoS2 layers is critical in practical applications as well as in basic researches. Various existing methods are currently available for the thickness measurement, but each has drawbacks. Transmission electron microscopy allows actual counting of the MoS2 layers, but is very complicated and requires destructive processing of the sample to the point where it will no longer be useable after characterization. Atomic force microscopy, particularly when operated in the tapping mode, is likewise time-consuming and suffers from certain anomalies caused by an improperly chosen set point, that is, free amplitude in air for the cantilever. Raman spectroscopy is a quick characterization method for identifying one to a few layers, but the laser irradiation causes structural degradation of the MoS2. Optical microscopy works only when MoS2 is on a silicon substrate covered with SiO2 of 100~300 nm thickness. The last two optical methods are commonly limited in resolution to the micrometer range due to the diffraction limits of light. We report here a method of measuring the distribution of the number of MoS2 layers using a low voltage field emission electron microscope with acceleration voltages no greater than 1 kV. We found a linear relationship between the FESEM contrast and the number of MoS2 layers. This method can be used to characterize MoS2 samples at nanometer-level spatial resolution, which is below the limits of other methods.
        4,000원