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        검색결과 16

        1.
        2022.11 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Interest in the use of semiconductor-based photocatalyst materials for the degradation of organic pollutants in a liquid phase has grown, due to their excellent performance and response to the light source. Herein, we fabricated a NiO-SiCTiO2 ternary structured photocatalyst which had reduced bandgap energy, with strong activation under UV-light irradiation. The synthesized samples were examined using XRD, SEM, EDX, TEM, DRS, EIS techniques and photocurrent measurement. The results confirmed that the two types of metal oxides were well bonded to the SiC fiber surface. The junction of the new photocatalyst exhibited a large number of photoexcited electrons and holes. The holes tended to oxidize the water and form a hydroxyl radical, which promoted the decomposition of methylene blue. The close contact between the 2D SiC fiber and metal oxide semiconductors expanded the scope of absorption wavelength, and enhanced the usability of the ternary photocatalyst for the degradation of methylene blue. Among three synthesized samples, the NiO-SiC-TiO2 showed the best photocatalytic effect, and was considered to have excellent photoelectron transfer due to the synergy effect between the metal oxide and SiC.
        4,000원
        2.
        2020.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Multi-walled carbon nanotubes (MWNTs) are suitable for delivering large biomolecules with lower cytotoxicity values and low prime cost. Surface modifications of MWNTs affect interaction with cells and proteins. Oxidation with strong acids decreases cytotoxicity of CNTs and increases protein-loading capacity. Here, after oxidation, TEM images revealed more aligned structure and carboxylated groups at the surface which decreases toxicity. Functionalized MWNTs showed more gradual degradation than the pristine MWNTs and mass loss increased by 2% in the same temperature range. Raman spectroscopy corrected graphitic structure with characteristic D and G bands at 1330 and 1579 cm−1 and increased intensity after oxidation. FTIR spectroscopy peaks at 1443 cm−1, 1560, 1640 cm−1, 2100–2200 cm−1 and 3426 cm−1 are ascribed to C–O–C vibrational stretch, C=C bonds, vibration of C≡C bonds and stretch of hydroxyl groups, respectively. The sonicationdriven dispersion of in phosphate-buffered saline, distilled water and cell culture medium were detected by UV–vis–NIR spectroscopy, water-dispersed functionalized MWNTs revealed the highest absorbance value. Cytotoxicity of MWNTs was investigated before and after functionalization in breast cancer (MDA-MB-231) and human vein endothelial (HUVEC) cells. Relatively low-toxicity results were obtained in functionalized MWNTs and cellular uptake of MWNTs were corrected with fluorescent imaging of cells and cell lysates. Protein-loading capacity of fsMWNTs (functionalized short-length multi-walled carbon nanotubes) was evaluated by using bovine serum albumin (BSA) and with an equal amount of fsMWNTs and BSA; 36% binding yield was obtained. Protein corona after covalent functionalization potentially lowered cytotoxicity up to 6%.
        4,200원
        3.
        2015.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 인체 유래 유방암세포인 MDA-MB-231 세포 증식을 억제하고 세포사멸을 유도하는 천연소재 발굴을 목적으로, 북한산 두릅 추출물을 MDA-MB-231 세포에 처리하여 세포사멸 및 작용기전을 규명하였다. 실험 결과, 두릅 추출물 처리 농도가 증가할수록 세포증식이 감소하였고, 세포질의 응축과 핵이 분절되는 등 apoptotic bodies를 형성하였다. 또한 유세포 분석기를 사용하여 MDA-MB-231의 세포주기가 억제되었고, 세포사멸의 특징인 sub-G1 수치가 증가되는 것이 관찰되었고, 두릅 추출물 농도가 증가함에 따라 apoptotic 세포가 유의적으로 증가하였으며, 특히 early apoptosis 보다 late apoptosis가 더 많이 진행됨을 확인할 수 있었다. 이를 바탕으로 MDA-MB-231 세포사멸과 관련된 유전자를 확인하고자 RT-PCR과 western blotting을 수행한 결과, 세포사멸의 주요한 조절인자인 anti-apoptotic인 bcl-2 발현이 두릅 추출물 처리 시 농도 의존적으로 감소되었고, 반대로 Bax의 발현은 증가됨을 확인하였다. 이를 통해 불활성화 형태로 존재한 pro-caspase-9과 pro-caspase-3의 발현이 시료 농도가 증가할수록 감소되었고, 활성화된 형태인 cleaved caspase-9과 cleaved caspase-3의 발현은 두릅 추출물 처리 농도에 의존적으로 증가하였다. 뿐만 아니라, 세포 사멸 과정의 주요 인자인 PARP 또한 시료 농도가 증가할수록 절단 현상이 비례적으로 증가하였다. 이상의 실험 결과를 근거로, 북한산 두릅 지상부의 70% ethyl alcohol 추출물이 MDA-MB-231 인체 유방암 세포의 증식을 억제하는 효과가 있음을 확인하였고, 세포사멸과 관련된 활성기전을 규명하였다. 추후 암 예방/치료제로서 두릅을 활용하기 위해서는 활성 본체와 안정성 규명 및 임상실험 등 추가 연구가 필요할 것으로 사료된다.
        4,000원
        4.
        2015.04 구독 인증기관·개인회원 무료
        With the increasing trend of global trades and protection of agro-ecosystem in importing and exporting countries, quarantine and pre-shipment(QPS) fumigation for perishable commodities are critical in terms of quality maintenance of fumigated commodities as well as eradicating quarantine pest. There are limited use of methyl bromide(MB) fumigation on fruits and vegetables due to not only worker safety issue at low temperature condition but phytotoxic damage to valuable commodities. We are here presented that commercial development of methyl bromide (MB) alternatives such as ethyl formate and phosphine gas formulated with carbon dioxide, that are increasing consumer and worker safety and avoiding phytotoxic damage in routine MB fumigation.
        5.
        2014.10 구독 인증기관·개인회원 무료
        For replacement of methyl bromide(MB) in Korea, there are several chemical options being introduced and developed in preplant and postharvest sections. In soil case, methyl-isothiocyanate(MITC) generating fumigant such as dazomet and metham sodium are currently being adapted for prevent from spreading soilborne disease and nematode, although there will be more successful application technology needed to develop in domestic circumstances. Also, ethanedinitrile(EDN), is newly developed chemical, could be one of the options to eradicate notorious soilborne diseases and nematodes near future. Ethyl formate(EF) now is showing the potential to replace MB in terms of consumer and worker safety and unwanted phytotoxic damage in routine MB fumigation. A phosphine gas(PH3) could be the last option to protect the import and export stored grains from stored grain insects and to solve the current issue such as PH3-resistant insect and consumer safety issues to replace metal phosphide. EDN also should be extended its use in not only timber and log fumigation in quarantine purpose but in use of national heritage and forest to keep wood infested pest safer. This presentation will be good opportunities to share the information and discuss with further research needs in current MB alterative program.
        6.
        2013.04 구독 인증기관·개인회원 무료
        Though quarantine use of methyl bromide(MB) is currently permitted in Korea, there has been phasing out and considering ban in many countries due to their ozone depletion properties. VapormateTM, a new gas formulation of ethyl formate(EF) with carbon dioxide, and VivakilTM, a new gas formulation of phosphine(PH3) with carbon dioxide, are MB alternative fumigants to methyl bromide(MB). For applying on import commodities, the efficacy of EF and PH3 was evaluated for 2hr fumigation on egg, nymph and adult stage of citrus mealybug(CMB), Planococcus citri, at two different temperatures(8, 13℃). The CT(Concentration X Time) product of EF to be expect 99% mortality to egg, nymph and adult stage of CMB were 108.3, 22.4 32.4 gh/m3 at 8℃ and 83.2, 25.1, 29.8 gh/m3 at 13℃, respectively. The CT product of PH3 gas to be expect 99% mortality to nymph and adult stage of CMB were 6.50, 2.55 gh/m3 at 8℃ and 3.72, 3.64 gh/m3 at 13℃, respectively. However, PH3 gas applied at high CT(4.2 gh/m3) for 2hr fumigation was not enough to obtain CT to egg stage of CMB at both temperature conditions. These efficacy data based on CT will be useful to predict the CT model in scale-up fumigation at diverse practical conditions.
        7.
        2012.10 구독 인증기관·개인회원 무료
        2011년 기준 국내 절화의 해외 수출액은 약 70백만불 수준으로, 이 중 5~10%가 검역해충으로 인해 수입국 현지 소독처리 되고 있다. 수입국의 현지 검역관리를 위해 사용 중인 Methyl bromide 훈증제는 오존층 파괴 물질로 향후 사용 제한될 예정이며, 절화 처리 시 약해로 인한 절화 품질 손상과 상품가격 하락으로 이어져 수출법인이 막대한 피해를 입고 있어 수입국의 검역 리스크를 감소시키고 수출절화의 품질을 유지 시킬 수 있는 MB 대체 훈증기술이 요구되고 있다. 본 연구에서는 MB 대체 훈증제인 phosphine 가스를 이용하여 수출절화장미의 검역해충 방제 효과를 검정하고자 소규모 실증시험 및 절화 수출 전문업체인 농업회사법인(주)로즈피아와의 현장적용평가를 실시하였다. 소규모 실증시험에서 절화장미의 주요 해충인 점박이응애, 꽃노랑총채벌레에 대한 99.9% 방제 CTP는 각각 33.6g h/m3, 17.9g h/m3로 확인되었으며, 절화장미 4개 품종에 대한 약해가 없었다. 40ft 절화 수출용 저온컨테이너를 이용한 현장시험에서는 PH3 2% 가스훈증제(상표명 비바킬)를 4℃에서 100g/m3, 15시간 처리 시 점박이응애, 담배가루이, 꽃노랑총채벌레를 99.9% 이상 방제하였으며, 절화장미 14종에 대한 유통 중 약해가 없어 향후 수출절화장미 검역훈증제로서 상업화 가능할 것으로 기대된다.
        8.
        2012.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Dye removal from waste water via adsorption by activated carbons (ACs) developed from agricultural wastes represents an ideal alternative to other expensive treatment options. Physical and chemical ACs were prepared from rice husks. The textural properties of the ACs were characterized by Brunauer-Emmett-Teller-N2 adsorption and scanning electron microscopy. The chemistry of the carbon surface was investigated by Fourier transform infrared spectroscopy, base and acid neutralization capacities, pH of the active carbon slurry, and pHpzc. The adsorption capacities of the ACs for the basic dye (methylene blue) and acid dye (acid green 25) were determined using parameters such as contact time, pH, and temperature. NaOH-ACs showed the highest surface area and total pore volume, whereas steam-ACs showed the lowest ones.
        4,300원
        9.
        2010.05 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The composite photocatalysts of a Fe-modified carbon nanotube (CNT)-TiO2 were synthesized by a two-step sol-gel method at high temperature. Its chemical composition and surface properties were investigated by BET surface area, scanning electron microscope (SEM), Transmission Electron Microscope (TEM), X-ray diffraction (XRD) and ultraviolet-visible (UV-Vis) spectroscopy. The results showed that the BET surface area was improved by modification of Fe, which was related to the adsorption capacity for each composite. Interesting thin layer aggregates of nanosized TiO2 were observed from TEM images, probably stabilized by the presence of CNT, and the surface and structural characterization of the samples was carried out. The XRD results showed that the Fe/CNT-TiO2 composites contained a mix of anatase and rutile forms of TiO2 particles when the precursor is TiOSO4·xH2O (TOS). An excellent photocatalytic activity of Fe/CNT-TiO2 was obtained for the degradation of methylene blue (MB) under visible light irradiation. It was considered that Fe cation could be doped into the matrix of TiO2, which could hinder the recombination rate of the excited electrons/holes. The photocatalytic activity of the composites was also found to depend on the presence of CNT. The synergistic effects among the Fe, CNT and TiO2 components were responsible for improving the visible light photocatalytic activity.
        4,000원
        10.
        2008.06 KCI 등재 구독 인증기관·개인회원 무료
        Cordyceps militarisis well known as a traditional herbal ingredient, which has been used for patients suffering from cancer in oriental medicine. In this study we have investigated the biochemical mechanisms of anti-proliferative effects by C. militarisextract(CME) in human breast cancer MDA-MB-231 cells. It was found that CME treatment induced chromatin condensation, mitochondrial energization, annexin V staining and sub-G1 phase DNAcontent. These indicators of apoptosis correlate with the mitochondrial dependent pathway, which results in the activation of caspase-3 activity. Both the cytotoxic effect by CME treatment were significantly inhibited by z-DEVD-fmk, a caspase-3 inhibitor,demonstrating the important role of caspase-3 in the observed cytotoxic effect. Cotreatment of CME and LY294002, resulted in significantly induction of apoptosis. These results indicate that caspase-3 is a key regulator of apoptosis in response to CME in human breast cancer MDAMB- 231 through downregulation of Akt, and that the C. militaris extract may therefore have therapeutic potential against human breast cancer.
        11.
        2007.12 KCI 등재 구독 인증기관·개인회원 무료
        Cordyceps militaris is well known as a traditional herbal ingredient, which has been used for patients suffering from cancer in oriental medicine. In this study we have investigated the biochemical mechanisms of anti-proliferative effects by C. militaris extract(CBE) in human breast cancer MDA-MB-231 cells. It was found that CBE treatment induced chromatin condensation, mitochondrial energization, annexin V staining and sub-G1 phase DNA content. These indicators of apoptosis correlate with the mitochondrial dependent pathway, which results in the activation of caspase-3 activity. Both the cytotoxic effect by CBE treatment were significantly inhibited by z-DEVD-fmk, a caspase-3 inhibitor, demonstrating the important role of caspase-3 in the observed cytotoxic effect. Co-treatment of CBE and LY294002, resulted in significantly induction of apoptosis. These results indicate that caspase-3 is a key regulator of apoptosis in response to CBE in human breast cancer MDA-MB-231 through down regulation of Akt, and that the C. militaris extract may therefore have therapeutic potential against human breast cancer.
        13.
        2007.06 구독 인증기관·개인회원 무료
        Cordyceps militaris is well known as a traditional herbal ingredient, which has been used for patients suffering from cancer in oriental medicine. In this study we have investigated the biochemical mechanisms of anti-proliferative effects by C. militaris extract(CBE) in human breast cancer MDA-MB-231 cells. It was found that CBE treatment induced chromatin condensation, mitochondrial energization, annexin V staining and sub-G1 phase DNA content. These indicators of apoptosis correlate with the mitochondrial dependent pathway, which results in the activation of caspase-3 activity. Both the cytotoxic effect by CBE treatment were significantly inhibited by z-DEVD-fmk, a caspase-3 inhibitor, demonstrating the important role of caspase-3 in the observed cytotoxic effect. Co-treatment of CBE and LY294002, resulted in significantly induction of apoptosis. These results indicate that caspase-3 is a key regulator of apoptosis in response to CBE in human breast cancer MDA-MB-231 through down regulation of Akt, and that the C. militaris extract may therefore have therapeutic potential against human breast cancer.
        14.
        1989.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Two cold-air outbreaks, one occurs in cold winter(1985-86) and the other in warm winter(1986-87) over Korea, are studied to represent maps of means, standard deviations maps and one-point correlation maps based on 1000mb and 500mb height fluctuations with different time scales during the cold-surge events. The filters are designed to isolate fluctuations with long time scales(periods longer than 70 days), intermediate time scales(10-70 day periods), short time scales(periods shorter than 10 days). The height fluctuations with long time scales are very similar to the climatological distributions of the wintertime geopotential height. In case of the intermediate time scales, the fluctuation fields reveal the long-wave patterns composed of 3-4 troughs and ridges around the midlatitude belt, in which trough along the East Asia coast and ridge over the Central Siberia and North Pacific are prominent and nearly stationary during the coldJsurge events. For short time scales, the dominent patterns consist of very short wave trains(wavelength 3000-4000㎞) which propagate sortheastward with a phase speed of 8-10 lat./days from the Barents Sea, through Northeast Siberia, toward Korea. The surface temperature fluctuations with small amplitude during the cold-surge events are coincident with this short wave trains passing through the Korean Peninsula.
        4,300원
        15.
        1981.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        이 시험은 수직 사이로에 충진된 옥수수를 대상으로 M.B를 사용하여 자연중력하에서 소독할 때 M.B가스의 침투확산성 및 살충효과를 요약하면 다음과 같다. 1. 사이로 표층의 M.B가스 농도는 투약후 2시간후부터 100mg/l 이상에서 20mg/l 이하로 급격히 감소하였다. 2. 사이로 표층으로부터 3m 깊이 지점의 M.B가스 농도는 투약후 12시간이후 100mg/l 이상에서 30mg/l 이하로 감소되었으며 표층의 고농도 M.B가스가 불과 30분 이내에 3m 깊이 까지 침투되었음을 알 수 있었다. 3. 사이로 표층으로부터 고농도의 M.B가스는 13m 깊이 지점까지 1시간 이내에 침투되었으며 투약후 48시간까지 지속적으로 100mg/l 이상40mg/l 이상의 M.B가스가 검지되는 것으로 보아 자연중력하에서 옥수수를 소독하는 경우 13m 깊이 부근에 M.B 가스의 고농도 대를 형성하는 것으로 추측된다. 4. 사이로 기부(21m 지점)의 M.B가스는 에 불과했던 것으로 보아 M.B의 침투가 아주 적었던 것으로 판단되어진다. 5. M.B 가스의 횡 확산성은 수직 침투성에 비하여 매우 적었으며 사이로 길이 3m의 경우 투약방향으로부터 약 13m지점의 qdnl는 중심부의 약 , 그리고 깊이 13m 지점에서는 지점에서는 의 농도에 불과하였다. 6. 투약후 24시간만에 조사한 사이로의 표층 및 기부(21m 지점)에 삽입 했던 공시충(거짓쌀도둑)은 모두 사멸되었으며 48시간후에 조사한 3m, 7m, 및 13m 지점의 공시충도 모두 사충으로 발견되었다.
        4,000원
        16.
        2008.02 KCI 등재 서비스 종료(열람 제한)
        Nelumbo nucifera Gaertn.(family Nymphaeaceae) has been used for summer heat syndrome as home remedy in Japan, China and Korea. Although whole plant parts are edible, root is commonly consumed. It has been reported that rhizome extract showed anti-diabetic and anti-inflammatory effects. However, in spite of usefulness for treatment of various diseases, the effect of Nelumbo nucifera rhizome(NNR) on proliferation, migration and matrix degrading enzymes-matrix metalloproteinsases(MMPs), the expression of which degrades extracellular matrix(ECM) leading to metastasis, has not been fully elucidated. We examined the effect of hot water extract of NNR on the proliferation, migration and secretion of MMP-2 and MMP-9 in rat smooth muscle cells(rSMC), epidermoid cancer cells(A431) and breast cancer cells(MDA-MB-231). The proliferation assay was carried out using MTT assay, the principle of which depends upon the conversion of MTT by mitochondrial dehydrogensases of viable cells to formazan crystals. The effect of NNR on migration of cells was examined using wound healing assay. Our results showed that there was inhibition in the proliferation, migration and expression of MMP-2 and MMP-9 in dose dependent fashion in all the cells used. Thus, we concluded that NNR could be used as traditional medicine in the treatment of various diseases where proliferation, migration and MMPs' expression plays a pathological role like in restenosis and metastasis.