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        검색결과 104

        1.
        2023.11 구독 인증기관·개인회원 무료
        Bis (2-ethylhexyl)phosphoric acid (HDEHP) is a renowned extractant, favored for its affinity to selectively remove uranium via its P=O groups. We previously synthesized HDEHP-functionalized mesoporous silica microspheres for solid-phase uranium adsorption. Herein, we investigated the kinetic and isothermal behavior of uranyl ion adsorption in mesoporous silica microspheres functionalized with phosphate groups. Adsorption experiments were conducted by equilibrating 20 mg of silica samples with 50 mL of uranium solutions, with concentrations ranging from 10 to 100 mgU L−1 for isotherms and 100 mgU L−1 for kinetics. Three distinct samples were prepared with varying HDEHP to TEOS molar ratios (x = 0.16 and 0.24) and underwent hydrothermal treatment at different temperatures, resulting in distinct textural properties. Contact times spanned from 1 to 120 hours. For x = 0.16 samples, it took around 50 and 11 hours to reach equilibrium for the hydrothermally treated samples at 343 K and 373 K, respectively. Adsorbed quantities were similar (99 and 101 mg g-1, respectively), indicating consistent functional group content. This suggests that the key factor influencing uranium adsorption kinetics is pore size of the silica. The sample treated at 373 K, with a larger pore size (22.7 nm) compared to 343 K (11.5 nm), experienced less steric hindrance, allowing uranium species to diffuse more easily through the mesopores. The data confirmed the excellent fit of pseudo-second-order kinetic model (R2 > 0.999) and closely matched the experimental value, suggesting that chemisorption governs the rate-controlling step. To gain further insights into uranium adsorption behavior, we conducted an adsorption isotherm analysis at various initial concentrations under a constant pH of 4. Both the Langmuir and Freundlich isotherm models were applied, with the Langmuir model providing a superior fit. The relatively high R2 value indicated its effectiveness in describing the adsorption process, suggesting homogenous sorbate adsorption on an energetically uniform adsorbent surface via a monolayer adsorption and constant adsorption site density, without any interaction between adsorbates on adjacent sites. Remarkably, differences in surface area did not significantly impact uranium removal efficiency. This observation strongly suggests that the adsorption capacity is primarily governed by the loading amount of HDEHP and the inner-sphere complexation with the phosphoryl group (O=P). Our silica composite exhibited an impressive adsorption capacity of 133 mg g-1, surpassing the results reported in the majority of other silica literature.
        2.
        2023.10 구독 인증기관·개인회원 무료
        Sweet pepper(paprika) belongs to the genus Capsicum, and is one of the most important export product from Korea to Japan and Southeast Asia. So it is important to eradicate plant quarantine pests before export sweet pepper. Aphids, whiteflies and mites are major pests that can damage to sweet peppers. Fumigation is normally used to eradicate pests in plant quarantine, but phytotoxicity may can be appeared that affect the quality of the product. Low-temperature treatment, one of the most popular physical treatment, can reduce crop damage to preserve product quality, but it takes long time to kill pests, which can cause quality degradation. In this study, phytotoxicity of fumigants, phosphine(PH3), ethyl formate(EF) and PH3+EF on sweet peppers was investigated to use as basic data for physicochemical treatment. When treated with more than 35 mg/L of EF, phytotoxicity was occurred, and was not occurred with PH3. When low-temperature of 1.7 degrees treated for 15 days after fumigation, it seems to be no direct damage from low-temperature treatment. But quality of top of sweet pepper was decreased from 7 days after fumigation.
        3.
        2023.10 구독 인증기관·개인회원 무료
        Because of recent reports about phosphine resistance problem, development of effective fumigation method to control grain pests became very important. In this study, a chemical treatment, ethyl formate fumigant treatment, and a physical treatment, atmospheric control, were attempted as alternative solutions to this problem. In this study, for CA(Controlled atmosphere) treatment, 99.999% nitrogen was used to create a hypoxic condition with less than 5% oxygen, and for EF, the treatment concentration was 10 mg/L to 80 mg/L. As a result of the study, in CA single treatment, adult insects showed a mortality rate of less than 10% even after 2 weeks of treatment, and pupae and larvae showed a mortality rate 71% and 34%, but eggs showed a mortality rate of 100%. In EF single treatment, adults and larvae showed a 100% mortality rate at 80 mg/L, but eggs showed a 50% mortality rate and pupae were not affected. Considering the results, CA single treatment is not suitable for controlling Tribolium castaneum because of long treatment period, and in the case of EF single treatment, additional researches on longer treatment time is needed.
        8.
        2023.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        국내 현대정원의 조성 디자인 경향성을 확인하고자 우수 경 관 정원 80개소 대상으로 적용 양식 및 정원 식물을 조사하였 다. 조사 대상 80개소 정원 중 53.7%는 서울 및 수도권, 46.3%는 그 외 지역에 소재하고 있다. 또한, 관리 유형에 따 라 공동 정원, 상업시설 정원, 개인 정원으로 구분 되었으며, 각 62.5%, 21.3%, 16.2%로 나타났다. 19~20세기 해외 정원 사조에 따라 조성 양식은 12유형(정형식, 비정형식, 정형 및 비정형 복합식, 건축식, 자연, 신풍경, 뉴저먼 스타일, 모더니 즘, 프레리 스타일, 뉴웨이브 스타일, 낭만주의, 예술작품 정 원)으로 분류되었다. 우리나라 현대 정원은 단일 및 복합 양식 활용이 각 55.0%와 45.0%로 유사하였다. 주로 정형 및 비정 형 복합식 정원이 활용되는 반면, 정형 및 비정형 복합식 정원 대비 낭만주의, 모더니즘, 프레리 및 뉴웨이브 스타일 이용 빈 도는 0.02~0.06배 수준이었다. 조성 양식 활용에 따라 이용 되는 식물 소재 유형에는 큰 차이가 없었으나, 특정 디자인에 서 식재 빈도가 높은 분류군을 확인했다.
        4,600원
        16.
        2022.09 구독 인증기관 무료, 개인회원 유료
        Ulva compressa Linnaeus (UCL) is a green algae seaweed that performs photosynthesis and is used as a food material in some Asian regions including Korea. It is known to be the dominant species in copper ion-contaminated seas, and many studies on copper ion resistant mechanisms have been reported. UCL is known to have an excellent antioxidant effect, but limited information is available regarding its other physiological activities. In this study, we investigated the anticancer activity of 30% prethanol extracts of Ulva compressa Linnaeus (30% PeUCL) and the underlying mechanisms of its activity on human FaDu hypopharyngeal squamous carcinoma cells. The 30% PeUCL extracts suppressed FaDu cell viability without affecting normal cells (L929), as determined by MTT and viability assays. Furthermore, the 30% PeUCL extracts induced apoptosis, as determined by DAPI staining. The 30% PeUCL extracts inhibited colony formation effectively as well as wound-healing of FaDu cells, even at noncytotoxic concentrations. In addition, 30% PeUCL extracts induced apoptosis significantly through proteolytic cleavage of caspase-3, -7, and -9, and poly (ADP-ribose) polymerase, and by downregulation of Bcl-2 and upregulation of Bax in FaDu cells, as determined by Western blot analysis. Collectively, these results suggest that the inhibitory effect of 30% PeUCL extracts on the growth of oral cancer cells, colony formation and wound-healing may be mediated by caspase- and mitochondrial-dependent apoptotic pathways in human FaDu hypopharyngeal squamous carcinoma cells. Therefore, 30% PeUCL extracts can be administered as a natural chemotherapeutic drug for the treatment of human oral cancers.
        4,000원
        19.
        2022.03 구독 인증기관 무료, 개인회원 유료
        Humulus japonicus (HJ) is a widely used herbal medicine for pulmonary tuberculosis, hypertension, leprosy, and venomous wounds in Asia, particularly in China. Although HJ has certain physiological activities, such as longitudinal bone growth, antioxidation and alleviation of rheumatism, its anticancer activities, other than in colorectal and ovarian cancer, are yet to be studied. In this study, we investigated the anti-cancer activity and mechanism of methanol extracts of HJ (MeHJ) against human FaDu hypopharyngeal squamous carcinoma cells. MeHJ suppressed FaDu cell viability without affecting normal cells (L929), which was demonstrated using the MTT and Live & Dead assays. Furthermore, MeHJ effectively inhibited colony formation of FaDu cells, even at non-cytotoxic concentrations, and significantly induced apoptosis through the proteolytic cleavage of caspase-9, -3, -7, poly (ADP-ribose) polymerase and through the downregulation of BCL-2 and upregulation of BAX in FaDu cells, as determined by DAPI staining, flow cytometry, and western blot analyses. Collectively, these findings suggest that the inhibitory effects of MeHJ on the growth and colony formation of oral cancer cells may be mediated by caspase- and mitochondrial-dependent apoptotic pathways in human FaDu hypopharyngeal squamous carcinoma cells. Therefore, MeHJ has the potential to be used as a natural chemotherapeutic drug against human oral cancer.
        4,000원
        20.
        2021.12 구독 인증기관 무료, 개인회원 유료
        Nypa fruticans Wurmb (NFW) contains a large amount of phenolic acid and flavonoids, and is popular as a superfood in Myanmar. NFW has various biological activities, such as anti-inflammatory, anti-oxidant, and neuroprotective properties; however, the anti-cancer effect of NFW have not been reported. In this study, we investigated the anticancer activity of water extracts of NFW (WeNFW) and the underlying mechanism in human FaDu hypopharyngeal squamous carcinoma cells. The WeNFW inhibited FaDu cell growth in a dose-dependent manner without affecting normal cells (L929), as determined by an MTT assay and Live and Dead assay. In addition, the concentrations of WeNFW without cytotoxicity (0.025, 0.05, and 0.1 mg/mL) inhibited wound healing and colony formation. Furthermore, WeNFW significantly induced apoptosis through the proteolytic cleavage of caspase-3 and -9, poly (ADP-ribose) polymerase, and downregulation of Bcl-2 and upregulation of Bax in FaDu cells, as determined by DAPI staining, FACS analysis, and western blot analysis. Taken together, these results suggest that WeNFW exhibits potent anti-cancer effects by suppressing the growth of oral cancer cells, wound healing and colony formation activity. Via mitrochondrial-dependent apoptotic pathways in human FaDu hypopharyngeal squamous carcinoma cells. Therefore, WeNFW can provide a natural chemotherapeutic drug for oral cancer in humans.
        4,000원
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