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        검색결과 77

        1.
        2024.03 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        Despite advancements in therapeutic approaches, radiotherapy and cisplatin-based chemotherapy remain primary noninvasive treatments for patients with oral squamous cell carcinoma (OSCC). Moreover, the 5-year survival rate for patients with OSCC has remained almost unchanged for several decades, and many side effects of chemotherapy still exist. In this study, three-dimensional (3D) models of OSCC were established using fibroblasts, and the efficacy of various biological inhibitors was evaluated. A culture of epithelial cells with two types of fibroblasts (hTERT-hNOFs and cancer-associated fibroblasts) within a type I collagen matrix resulted in the formation of a continuous layer of tightly packed cells compared to models without fibroblasts. Furthermore, the effects of biological chemicals, including Y27632, latrunculin A, and verteporfin, on these models were investigated. The stratified formation of the epithelial layer and invasion in OSCC 3D-culture models were effectively inhibited by verteporfin, whereas invasion was weakly inhibited by Y27632 and latrunculin. Collectively, the developed OSCC 3D-culture models established with fibroblasts demonstrated the potential for drug screening, with verteporfin showing promising efficacy.
        4,000원
        2.
        2023.11 구독 인증기관·개인회원 무료
        It is crucial to be sure about the safety of nuclear facilities for human resources who are in danger of radioactive emission, also diminishing the volume of the wastes that are buried under the ground. Chemical decontamination of nuclear facilities can provide these demands at the same time by dissolving the oxide layer, which radionuclides such as 60Co and 58Co have been penetrated, of parts that are utilized in nuclear plants. Although there are many commercial methods to approaching its aim and they perform a high decontamination factor, they have some issues such as applying organic acids which have the ability to chelate with radionuclides that can be washed by underground water, have large quantities of radioactive waste and damage to the surface by severe intergranular attack. A new method has been introduced by KAERI’s scientist which is named the HyBRID Process, in this process the main solution is the acidic form of Hydrazine. In this process, like other acid-washing processes, there is a chance of corrosion on the metal surface which is not desired. The metal surface is able to be protected during dissolving process by adding some organic and inorganic corrosion inhibitors such as PP2 and PP3. There is a very new research topic about ionic liquids (ILs) as corrosion inhibitors which illustrates a vast potential for this application due to their tunable nature and the variety of options for cationic and anionic parts. The key factors for ILs corrosion inhibitors such as the hardness properties are summarized. In this study, we review to the fundamentals and development of corrosion inhibitors for chemical decontamination and give an prospect with emphasis on the challenges to be overcome.
        3.
        2023.05 구독 인증기관·개인회원 무료
        KAERI has been developing a new decontamination process that does not contain any organic chemicals in the decontamination solution and minimizes the use of ion exchange resin in the solution as a purifying step. The process is hydrazine based reductive metal ion decontamination for decommissioning (HyBRID) and consists of N2H4, H2SO4 and Cu+ ions. The primary system of the LWR is composed of materials with high corrosion resistance, such as stainless steel and Inconel, but among the materials, the feeder and header of the primary system of the PHWR are composed of carbon steel (SA106Gr.B) with low corrosion resistance. Therefore, when decontamination of PHWRs, attention should be paid to corrosion of carbon steel. Since Fe3O4, a contaminating oxide film formed on the surface of carbon steel dissolves faster than ferrite or chromite formed on the surface of Inconel or stainless steel, the base material is exposed to the solution and is corroded during decontamination. When a large amount of iron ions is eluted into the decontamination agent due to corrosion of carbon steel, not only the soundness of the base metal is adversely affected, but also the amount of decontamination waste increases. The purpose of this study is to develop inhibitors that can minimize corrosion of carbon steel when decontamination of PHWRs using the HyBRID decontamination process. CG, 570S and PP3 were selected as corrosion inhibitors. In addition, corrosion tests of carbon steel were conducted in the HyBRID solution with corrosion inhibitors. The best corrosion inhibitors and optimal operating conditions were selected, and HyBRID decontamination agents with corrosion inhibitors were much better in corrosion resistance than existing commercial decontamination agents.
        5.
        2022.05 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Corrosion is a natural, inevitable process, and is one of the world's most serious problems. Losses incurred due to corrosion are extremely expensive for society. Several technological strategies have been explored and implemented to address these losses. The use of inhibitors to prevent corrosion is a common and efficient method to reduce corrosion losses. This review covers Al and Al-composite corrosion inhibitors in chloride-containing solutions, because of their popularity in a broad array of industrial applications. A vast number of studies in the literature detail the common tendency of Al and Al-composites with reinforcements to deteriorate. Accordingly, it is worthwhile to employ inhibitors to protect them, as discussed in the present work. The emphasis is on selecting the smartest corrosion inhibitor and evaluating its performance. According to the study, the most commonly used corrosion inhibitors are 1,4-naphthoquinone (NQ), 1,5-naphthalene diol, 3-amino-1,2,4-triazole-5-thiol (ATAT), ammonium tetrathiotungstate, clotrimazole, amoxicillin, antimicrobial and antifungal drugs. Electrochemical impedance spectroscopy (EIS), potentiodynamic (PDP), and weight loss were among the most commonly used modern electrochemical technologies to test inhibitors’ efficacy under environmental conditions.
        4,000원
        7.
        2019.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We observed MMPs expression in all sperm groups, with pro-MMP showing lower expression than active MMPs. According to the results from each freezing extender, the sperm membrane integrity (HOST: Hypoosmotic Swelling Test) analysis in TCGGD (Tris 250 mM, Citric acid 88 mM, Glucose 47 mM, Glycerol 3%, Dimethylsulpoxide 3.5 M) is 59.8 ± 0.7, TCGSD (Tris 250 mM, Citric acid 88 mM, Glucose 47 mM, Sucrose 0.1 M, Dimethylsulpoxide 3.5 M) is 59.3 ± 0.5 were significantly higher (p < 0.05) among the experimental groups. And MMPs analysis result, we observed MMPs expression in all sperm groups, with pro-MMP showing lower expression than active MMPs. The expression of active MMP-2 was the highest in sperms frozen in TCGSD and TCGD (Tris 250 mM, Citric acid 88 mM, Glucose 47 mM, Dimethylsulpoxide 3.5 M), Meanwhile, sperms from the TCGGD and TCGED (Tris 250 mM, Citric acid 88 mM, Glucose 47 mM, Ethylene glycol 3%, Dimethylsulpoxide 3.5 M) group showed lower level of active MMP-2 expression. Together, these results indicate that adding glycerol or sucrose to the sperm freezing buffer would not only suppress MMPs expression but also minimize DNA fragmentation, providing a mean to improve the success rate in the in vitro manipulation of rabbit sperms. Therefore, these results suggest that TCGGD or TCGSD extender method for freezing-thawing of rabbit sperm increased the viability after thawing.
        4,000원
        8.
        2019.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Succulents are ornamental plants that are popularly used in landscaping and as potted plants. Miniatureplants that are planted in miniature pots for small spaces or tables, or in elaborateaccessories such as key chains, key holders or hanging pots, have recently become more popular. Their unique characteristics and aesthetic appeal have increased their demand especially for those species that do not grow extensively during transport or for special cases in which they are placed into tiny containers to be used in key chains. This study investigated the effects of the plant growth inhibitors chlormequat, paclobutrazol, and daminozide, on two Echeveria species, Echeveria ‘A Grimme One’ and Echeveria ‘Little Rose’. Results revealed that the plant growth inhibitors successfully controlled the growth of Echeveria species at specific concentrations. Among the inhibitors applied to the succulents, paclobutrazol at 100 ppm was found to be the most effective treatment for both the species.
        4,000원
        9.
        2018.05 구독 인증기관·개인회원 무료
        바이오파울링은 역삼투막 여과 공정에서 운전 성능을 저해하는 주요 원인이다. 이전 연구들은 분리막 표면에 발생하는 바이오파울링을 제어하기 위해서 화학적 세정제를 주입하는 방법을 주로 사용하였다. 화학적 세정제의 주입은 분리막의 손상뿐만 아니라 이차적으로 수계 오염을 발생시키기 때문에 주입 농도와 운영 방법에 주의가 요구된다. 이러한 문제를 극복하기 위해, 본 연구에서는 분리막 표면에 생물막 저해제를 고정하여 바이오파울링을 제어하는 연구를 수행하였다. 표면 고정화를 위한 방법으로 Layer-by-layer 기술을 적용하였고, 생물막저해제로 클로르헥시딘과 글루타알데하이드를 사용하였다. 막 표면의 생물막 저해제 고정화는 미생물의 부착 억제 및 사멸로 생물막 형성이 지연되어 운전 성능이 유지되는 효과를 나타냈다.
        10.
        2018.04 구독 인증기관·개인회원 무료
        The entomopathogenic bacteria Xenorhabdus/Photorhabdus inhibit insect immune responses by inhibiting eicosanoid biosynthesis. Especially, the bacterial secondary metabolites inhibit PLA2 that release eicosanoid biosynthesis precursors. Some organic extracts of the bacteria-cultured broth possessed PLA2 inhibitory activity. This study used butanol to extract the metabolites and showed that the extract possessed potent inhibitory activity against insect immunity. The inhibition was reversed by the addition of eicosanoid biosynthesis precursor, suggesting PLA2 inhibition. Furthermore, sub-fractionation of the butanol extract separated the secondary metabolites and the fractions exhibited differential PLA2 inhibition. The active fractions appeared to contain novel compounds that are not known in PLA2 inhibition of these bacteria.
        11.
        2017.09 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        Ras activates a series of downstream effectors, including the mitogen-activated protein kinase pathway and the Rac/Rho pathway after insulin stimulation. Mutations in Ras are found in approximately 30% of all human cancers and are critical factors in tumor initiation and maintenance. There are four Ras proteins with 80-90% amino acid sequence homology with major differences in the carboxyl termini. Ras proteins undergo farnesylation on their carboxyl termini catalyzed by the enzyme protein farnesyltransferase (FTase), which facilitates localization of Ras proteins to the inner surface of the plasma membrane. Because inhibition of FTase would prevent Ras from processing into its active form, FTase is viewed as a potential therapeutic target. A variety of FTase inhibitors have showed great potency against tumor cells in preclinical studies. Although many farnesyltransferase inhibitors have been developed, their adverse effects on the mitogenic and metabolic actions of insulin are not completely understood. Here we show that YH3096, a farnesyltransferase inhibitor, inhibits insulin-mediated DNA synthesis in HIRc-B cells without affecting c-Jun expression and membrane ruffling in HIRc-B cells. Moreover, YH3096 and its derivatives did not affect insulin-induced glucose uptake in 3T3-L1 adipocytes. Our results provide a laboratory evaluation of the effects of Ras inhibitors on insulin functions.
        4,000원
        12.
        2017.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The objectives of the present study were to investigate the effect of five chemical inhibitors on methane production of the pure cultures of methanogens. To examine the methanogenesis inhibition by 2-bromoethane sulfonic acid (BES), 3-bromopropane sulfonic acid (BPS), lumazine, propynoic acid and ethyl 2-butynoate, they were added into the pure cultures of Methanobacterium formicicum KOR-1 and KOR-12, Methanoculleus bourgensis KOR-2, Methanosarcina mazei KOR-3, KOR-7, KOR-9 and KOR-10, Methanosarcina vacuolata (DSM 1232), Methanobacterium bryantii (ATCC 33272), Methanosarcina mazei (ATCC BAA159) and Methanosarcina barkeri (ATCC 43240). Each methanogen was anaerobically incubated at 39℃ for 6 and 10 days, and then methane gas production was measured. All methanogens were sensitive to BES, lumazaine and ethyl 2-butynoate and as the addition levels of the chemicals increased, the methanogenesis was linearly reduced. BPS and propynoic acid failed to inhibit any of the methanogens. There were important differences among species of methanogens regarding their sensitivity to the different inhibitors. In general, the strains of Methanosarcina species were the most resistant to BES, lumazaine and ethyl 2-butynoate and the strains of Methanobacteriales order the least resistant. The different resistances to chemical inhibitors may be caused by different cell membrane structure, substrate utilization for methanogenesis and competition with other microorganisms for electron receptors. In conclusion, differences among methanogens habituating in anaerobic ecosystems, such as the rumen of ruminants regarding their resistance to chemical inhibitors should be considered when strategies of inhibition of methanogenesis are designed.
        4,300원
        13.
        2017.03 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        Bovine viral diarrhea virus (BVDV) is a major pathogen that may be one of the main reasons for economic losses in the livestock industry. BVDV is a well-characterized member of Flaviviridae family with plus-stranded RNA viruses. Non-structural NS5B protein is RNA-dependent RNA polymerase, which is responsible for viral RNA synthesis and genome replication of BVDV. Therefore, the NS5B polymerase is a key target for the discovery of anti-BVDV drugs. A number of small-molecule inhibitors against the NS5B polymerase have been reported in literature of which we collected series molecules having various scaffold with their biological data determined by evident experimental conditions, methods and procedures. Then, we constructed database of 655 small-molecule NS5B inhibitors having definitive activity values, structural parameters, and physicochemical properties (such as molecular hydrophobicity, hydrophilicity, polarity, Hbond donors and H-bond acceptors) associated with their absorption and permeability through a cheminformatics approach. The database was opened to provide insight for allosteric NS5B inhibitors of BVDV with an accessible platform on the web (http://nabic.rda.go.kr/chemical genomic database/BVDV RNA dependent RNA polymerase inhibitors). This molecular information in the database would be useful in attempting to identify features and decision factors that enhance anti-BVDV activity or increase selectivity of the allosteric inhibitor. These anti-BVDV molecules could also be screening for the purpose of exploiting potent NS5B inhibitors in the same family (e.g., HCV, CSFV, YFV, WNV, and DENV).
        4,200원
        14.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        To improve the developmental potential of bovine somatic cell nuclear transfer (SCNT) embryos, this study compared the developmental rates to blastocyst stage in the SCNT embryos using donor fibroblasts treated with 5-azacytidine (5AC) and S-adenosylhomocysteine (SAH) at different concentrations. Their reprogramming efficiency level was investigated with level of telomerase activity. Donor fibroblasts isolated from adult ear skin of a cow were exposed to 5AC and SAH at different concentrations during 2 passages. After nuclear transfer into enucleated recipient oocytes, the cleavage and developmental rates were significantly (p<0.05) decreased in the SCNT embryos using 5AC-treated fibroblasts (5AC-SCNT embryos), compared with those of non-treated control (control-SCNT embryos) and SAH-treated fibroblasts (SAH-SCNT embryos). The developmental rates to blastocyst stage tended to be slightly increased in the SAH-SCNT embryos at each of the concentrations, and especially, the developmental rates in the SCNT embryos using 1.0 mM SAH-treated fibroblasts were significantly (p<0.05) higher than that of control SCNT embryos. The mean numbers of total and ICM cell in blastocysts were also significantly (p<0.05) decreased in the 5AC-SCNT embryos, compared with those of other SCNT blastocysts. Further, the level of telomerase activity was also significantly (p< 0.05) decreased in the 5AC-SCNT embryos than those of control and SAH-SCNT embryos. Whereas, a significantly (p<0.05) up-regulated telomerase activity was observed in SAH-SCNT embryos, compare with that of control-SCNT embryos. In conclusion, SCNT embryos using hypomethylated donor cells with SAH, not 5AC, may improve the developmental potential and reprogramming efficiency.
        4,000원
        15.
        2013.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        70% 에탄올로 양파를 추출한 다음 감압하에 농축하였고, 농축된 양파 추출물을 증류수에 재 용해시킨 용액의 pH는 5.34인 약산성으로 나타났다. 그리고 이 용액을 0.1 N NaOH 로 적정한 다음 TLC(전개용매: ethyl acetate)에서의 분리는 적 정 전보다 chromatogram의 이동 및 분리가 뛰어난 것으로 나 타났고, GST 활성 저해에도 유의성이 있는 것으로 나타났다. Silica-gel column chromatography에서 0.1 N NaOH 적정용액의 분리는 ethyl acetate(분획 A), methanol(분획 B), 50% methanol (분획 C)로 용출하였고, 용출된 각 분획은 감압하에 농축하여 GST 활성 저해 실험을 하였다. 세 부분 모두 GST 활성 저해에 유의성이 있는 것으로 나타났다. 각 분획은 GC-MS spectrometer 분석에서 두 종류 이상이 함유되어 있지만, 구성 물질은 서로 상이함을 보였고, 이들 물질의 분리와 구조 규명이 필요한 것 으로 사료된다.
        4,000원
        16.
        2013.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        주요 수출버섯인 큰느타리버섯의 적합한 수확 후관리방법을 개발하기 위해 저온 저장 후 유통온도와갈변방지처리에 따른 품질변화를 분석한 결과, 수확후 예냉단계에서 ClO₂ 처리를 하여 포장하여 저온저장 후 20°C 유통시 무처리보다 신선도가 우수했으며,10~15°C에서 유통할 때는 18일까지 판매가능한 신선도가 유지되어 무처리보다 3~6일 연장되어 농가에서출하 후 매장까지 신선도 유지에는 낮은 온도관리가가장 주요한 요인임을 확인할 수 있었다.
        4,000원
        19.
        2012.05 구독 인증기관·개인회원 무료
        I conducted experiments in Drosophila to investigate the consequences of altered acetylcholinesterase (AChE) activity in the nervous system. In ace hypomorphic mutant larvae, the amount of ace mRNA and the activity of AChE both in vivo and in vitro were significantly reduced compared with those of controls. Reduced Ace in Drosophila larvae resulted in significant down-regulation of branch length and the number of boutons in Type 1 glutamatergic neuromuscular junctions (NMJs). These defects in ace hypomorphic mutant larvae were suppressed when Musca domestica AChE was transgenically expressed. Because AChE inhibitors are utilized for medications for Alzheimer’s disease, we investigated whether pharmacological inhibition of AChE activity induced any synaptic defects. I found that controls exposed to a sublethal dose of DDVP phenocopied the synaptic structural defects of the ace hypomorphic mutant. These results suggest that down-regulation of AChE activity, regardless of whether it is due to genetic or pharmacological manipulations, results in altered synaptic architecture. This study suggests that exposure to AChE inhibitors for 6-12 months may induce altered synaptic architectures in human brains with Alzheimer’s diseases, similar to those reported here. These changes may underlie or contribute to the loss of efficacy of AChE inhibitors after prolonged treatment.
        20.
        2011.10 구독 인증기관·개인회원 무료
        Although somatic cell nuclear transfer (SCNT) has successfully been produced cloned animals in several species, the cloning efficiency is extremely low. It is generally believed that the low cloning efficiency is mainly attributed to faulty epigenetic modifications underlying the aberrant reprogramming of donor cell nuclei in recipient cytoplasm after SCNT. The nuclear reprogramming process involves epigenetic modifications, such as DNA demethylation and histone acetylation, which may be a key factor in improving the cloning efficiency. Recently, the histone deacetylase inhibitors (HDACi), such as trichosatin A (TSA) and m-carboxycinnamic acid bishydroxamide (CBHA), to increase histone acetylation have been used to improve the developmental competence of SCNT embryos. Therefore, we compared the effects of TSA with CBHA on the in vitro developmental competence and pluripotency-related gene expressions (Nanog, Oct3/4 and Sox2) in porcine cloned blastocysts. The porcine cloned embryos were treated with a 50 nM concentration of TSA or a 100 μm concentration of CBHA during the in vitro early culture (10h) after cell fusion and then were assessed to cleavage rate, development to the blastocyst stage and pluripotency-related gene expressions in NT blastocysts. All data was analyzed by chi-square. Following 4-5 replicates (245, 200 and 222 for NT, TSA and CBHA treated NT embryos respectively) there was no difference between normal NT and CBHA treated NT embryos, whereas TSA treated NT embryos was significantly decreased for cleavage rate (p<0.05). The developmental competence to the blastocyst stage in CBHA treated NT embryos (18.9%) significantly increased than that of normal NT and TSA treated NT embryos (9.4% and 11.5%) (p<0.05). In addition, all of pluripotent transcription factors (Nanog, Oct3/4 and Sox2) were highly expressed in the CBHA treated NT embryos, however, Sox2 and Oct3/4 were expressed in TSA treated NT embryos and Sox2 was only expressed in normal NT embryos (p<0.05). In conclusion, the treatment of CBHA as a histone deacetylase inhibitor significantly increased the developmental competence of porcine NT embryos and pluripotency- related gene expressions (Nanog, Oct3/4 and Sox2) in NT blastocysts.
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