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        검색결과 618

        41.
        2022.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Alzheimer's disease (AD) is one of the most common forms of dementia, affecting more than 50 million people globally. The onset of AD is linked to age, smoking, obesity, hypercholesterolemia, physical inactivity, depression, gender, and genetics of an individual. The accumulation of Aβ peptides and neurofibrillary tangles (NFTs) in the brain is one of the critical factors that lead to AD, which is known to disrupt neuronal signaling and causing neurodegeneration. As per the current understanding, inhibiting the accumulation of Aβ peptides and NFTs is crucial in the management/treatment of AD. Latest research studies show that nanoparticles have the potency of improving drug transport across the blood–brain barrier easily. Specifically, graphene quantum dots (GQDs), a type of semiconducting nanoparticles, have been established as effective inhibitors for blocking the aggregation of Aβ peptides. The small size of GQDs allows them to pass through the blood– brain barrier with ease. Moreover, GQDs have fluorescence properties, which can be used to detect the concentration of Aβ in vivo. In recent years, compared to other carbon materials, the low cytotoxicity and high biocompatibility of GQDs, give them an advantage in the suitability and clinical research for AD. In this manuscript, we have discussed the role of different types of nanoparticles in the transportation of encapsulated or co-assembled compound drugs for the treatment of AD and importantly, the role of GQDs in the diagnosis and management/treatment of AD.
        4,600원
        42.
        2022.10 구독 인증기관·개인회원 무료
        Radioactive waste containing cellulosic materials such as cotton, paper and wood are being disposed in Low-and intermediate-level radioactive waste disposal site in Gyeongju. Cellulose has recently emerged great issue in terms of disposal site safety as it can be decomposed into an organic complex compound, ISA (isosaccharinic acid), under strong alkali conditions (pH 12.5 or higher) formed by the hydrated cement, to accelerate the mobility of the radionuclides in the disposal facility. However, in Korea, there are insufficient criteria for confirming the suitability for disposal of low-and intermediatelevel radioactive wastes including cellulose, and there is no specific method for evaluating the total amount of waste to confirm the suitability of disposal. Therefore, the method of SKB (Swedish Nuclear and Fuel Management Company), which has established acceptance criteria related to the physicalchemistry safety of cellulose, is analyzed to suggest a method for deriving the amount of cellulosecontaining waste disposal. Cellulose, an organic complexing agent, is an important consideration for safety case at the Swedish low-and intermediate-level radioactive waste disposal site SFR. SKB calculated the amount of cellulose generated by separately labeling cellulose-containing wastes of 1-2BMA, Silo and 1BTF (SKB 2013). BLA, a low-level radioactive waste disposal facility, is not considered due to its low radionuclide inventory (~0.2% of SFR’s total radionuclide inventory, SKB 2013). To calculate the amount of cellulose that can be disposed of, information on the mass and volume of hydrated cement (concrete waste, cement solidification waste, disposal container, grouting, disposal shed), the concentration of ISA absorbed in the hydrated cement, and the concentration of ISA dissolved in the groundwater which were used. In addition, the total disposable amount was calculated using the cellulose degradation rate, composition ratio, and the cellulose containing waste volume.
        51.
        2022.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Chlorine dioxide (ClO2) has recently emerged as an ideal disinfectant and has shown a wide range of antimicrobial activities in various pathogenic microorganisms. In this study, the virucidal effect of ClO2 at low concentration (0.02 ppm) and higher concentration (0.06 – 0.09 ppm) against Adenovirus and Herpesvirus was evaluated based on the NF T 72-281 and ASTM 1053-11 standard methods at different exposure times. The virus suspension was dried onto the carrier and then exposed to gaseous ClO2 (gClO2) at 22 ± 2∘C. For Adenovirus, exposure at a low concentration of ClO2 at the middle height resulted in the average log10 reduction of 0.95, 2.65, and 5.30 after 1, 3, and 6 h post-exposure (pe), respectively. Moreover, more than 4-log10 reduction was achieved at 4 and 6 h pe with higher concentrations of ClO2. On the other hand, the antiviral activity of gClO2 at the middle height was also effective against Herpesvirus. In particular, at 1 h pe, a less than 4-log10 reduction was observed at all examined concentrations of ClO2, whereas exposure for 3 and 6 h (with low concentration) or 2 h (with higher concentration) inactivated completely viruses attached to the carrier. These results suggested that ClO2 fumigation is a potential alternative method for disinfecting healthcare facilities, high-containment laboratories, and households with a safe concentration for human health.
        4,000원
        52.
        2022.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Aluminum (Al) is one of the major factors adversely affects crop growth and productivity in acidic soils. In this study, the effect of Al on plants in soil was investigated by comparing the protein expression profiles of alfalfa roots exposed to Al stress treatment. Two-week-old alfalfa seedlings were exposed to Al stress treatment at pH 4.0. Total protein was extracted from alfalfa root tissue and analyzed by two-dimensional gel electrophoresis combined with MALDI-TOF/TOF mass spectrometry. A total of 45 proteins differentially expressed in Al stress-treated alfalfa root tissues were identified, of which 28 were up-regulated and 17 were down-regulated. Of the differentially expressed proteins, 7 representative proteins were further confirmed for transcript accumulation by RT-PCR analysis. The identified proteins were involved in several functional categories including disease/defense (24%), energy (22%), protein destination (9%), metabolism (7%), transcription (5%), secondary metabolism (4%), and ambiguous classification (29%). The identification of key candidate genes induced by Al in alfalfa roots will be useful to elucidate the molecular mechanisms of Al stress tolerance in alfalfa plants.
        4,000원
        53.
        2022.08 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We present the analysis of a planetary microlensing event OGLE-2019-BLG-0362 with a shortduration anomaly (∼0.4 days) near the peak of the light curve, which is caused by the resonant caustic. The event has a severe degeneracy with Δχ2 = 0.9 between the close and the wide binary lens models both with planet-host mass ratio q ≃ 0.007. We measure the angular Einstein radius but not the microlens parallax, and thus we perform a Bayesian analysis to estimate the physical parameters of the lens. We find that the OGLE-2019-BLG-0362L system is a super-Jovian-mass planet Mp = 3.26+0.83 −0.58 MJ orbiting an M dwarf Mh = 0.42+0.34 −0.23 M⊙ at a distance DL = 5.83+1.04 −1.55 kpc. The projected star-planet separation is a⊥ = 2.18+0.58 −0.72 AU, which indicates that the planet lies beyond the snow line of the host star.
        4,000원
        54.
        2022.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A thermally conductive film can be used to laterally conduct heat along the surface of glass windows, toward its edges where a heat sink could be located, thereby reducing temperature differential between the inside and outside surfaces of the window and thus lowering cross-sectional conductive heat transfer. This technique can offer optimized thermal energy management to modern buildings without the weight and cost of double- or triple-glazed window panels. In this work, a thermally conductive film was developed using carbon dots with inherently high thermal conductivity. Nitrogen atoms were then added to the carbon dots structure to intensify high-frequency phonon that would result in higher lateral thermal conductivity. The nitrogen-decorated carbon dots (NCDs) were prepared by a simple hydrothermal synthesis of citric acid with the addition of ethylenediamine as the N source. The NCDs were added to a cellulose-based solution and drop-casted onto FTO glass resulting in a transparent, laterally thermally conductive film, that also blocks ultraviolet (UV) and high-intensity blue light radiation. The visible-light transmission of the NCDs’ film was found to be up to 65%, comparable to the commercial solar films. The lateral thermal conductivity of the NCDs’ film increases with increasing N content up to an optimum level, suggesting the role of N to “concentrate’ the high-frequency phonons responsible for effective lateral thermal conductivity of the films.
        4,000원
        55.
        2022.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        As frontier materials, graphene oxide (GO) and graphene have penetrated almost all research areas and advanced numerous technologies in sensing, electronics, energy storage, catalysis, water treatment, advanced composites, biomedical, and more. However, the affordable large-scale synthesis of high-quality GO and graphene remains a significant challenge that negatively affects its commercialisation. In this article, firstly, a simple, scalable approach was demonstrated to synthesise high-quality, high yield GO by modifying the improved Hummers method. The advantages of the optimised process are reduced oxidation time, straightforward washing steps without using coagulation step, reduction in cost as eliminating the use of phosphoric acid, use of minimum chemical reagents, and increased production of GO per batch (~ 62 g). Subsequently, the produced GO was reduced to reduced graphene oxide (rGO) using three different approaches: green reduction using ascorbic acid, hydrothermal and thermal reduction techniques. The GO and rGO samples were characterised using various microscopy and spectroscopy techniques such as XRD, Raman, SEM, TEM, XPS and TGA. The rGO prepared using different methods were compared thoroughly, and it was noticed that rGO produced by ascorbic acid reduction has high quality and high yield. Furthermore, surface (surface wettability, zeta potential and surface area) and electrical properties of GO and different rGO were evaluated. The presented synthesis processes might be potentially scaled up for large-scale production of GO and rGO.
        4,900원
        56.
        2022.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Due to its capacity to manufacture low-cost 3D-printed structures, 3D-printing technology offers a unique opportunity for the fast epitome of various applications. Using a typical fused deposition modeling 3D printer along with a Discovery extruder, a graphene-ink can be 3D printed to produce an interdigitated electrode (IDE) arrangement. This work fabricated a 3D-printed planar supercapacitor from pristine graphene-ink without using high-temperature processing or functional additives. The printable ink (89%) is formulated from pristine graphene without the addition of any functional additives. The symmetric flexible supercapacitor is demonstrated with an excellent specific capacitance of 137.50 F/g at 0.5 A/g and an energy density of 12.23 Wh/kg. The obtained gravimetric energy density beats reported earlier carbon-based supercapacitors that are 3D or inkjet printed. The flexibility and robustness of 3D-printed devices are achieved up to 150° folding angles. This work demonstrates an efficient and easy method for fabricating practical energy storage devices featuring a customizable shape and excellent flexibility.
        4,000원
        58.
        2022.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        고객의 ‘갑질’로부터 서비스 조직 구성원을 보호해야 한다는 논의가 활발하게 이루어지면서 고객의 비인 격적인 행동에 대한 관심이 높아지고 있다. 고객의 무례한 행동(customer incivility)로 인하여 서비스 조직 의 구성원들은 심리적으로 큰 어려움을 겪고 있으며, 우울증과 극단적 선택까지 고려하는 상황이 되었다. 이러한 점에서 조직은 고객의 무례한 행동의 부정적 결과를 인식하고 이를 개선하기 위한 노력이 필요하다. 본 연구에서는 고객의 무례한 행동이 스트레스를 통해 서비스 몰입과 이직의도에 미치는 과정에서 작용하 는 메커니즘을 확인하는 목적으로 수행되었다. 특히, 고객의 무례한 행동이 구성원들에게 미치는 부정적 효과를 보다 엄격하게 확인하기 위하여, 조직 내부에서 발생할 수 있는 직속상사의 비인격적 감독(abusive supervision)을 통제하였다. 가설검증을 위하여 2019년 5월에서 8월 사이 수도권 서비스직 종사자를 대상 으로 설문조사를 실시하였으며, 최종 205개의 설문을 기반으로 실증분석을 실시하였다. 본 연구의 분석 결과 고객의 무례한 행동은 구성원들의 서비스 몰입을 낮추고, 이직의도를 높이는 것으로 조사되었다. 또한 이 과정에서 스트레스가 매개 효과를 가짐을 확인하였다. 본 연구는 실증분석 결과를 바탕으로 이론적·실무 적 시사점을 논의하였으며, 향후의 연구 과제를 제시하였다.
        5,700원
        59.
        2022.05 구독 인증기관·개인회원 무료
        To obtain confidence in the safety of disposal facilities for radioactive waste, it is essential to quantitatively evaluate the performance of the waste disposal facilities by using safety assessment models. Thus, safety assessment models require uncertainty management as a key part of the confidencebuilding process. In application to the numerical modelling, the global sensitivity analysis is widely employed for dealing with parametric and conceptual uncertainties. In particular, the parametric uncertainty can be effectively reduced by minimizing the uncertainty of critical parameters in the safety assessment model. In this paper, the numerical model of each step disposal facility (Silo, Near surface, and Trench type) at Wolsong Low and Immediate Level Waste (LILW) Disposal Center is designed by using a two-dimensional finite element code (COMSOL Multiphysics). In order to determine the critical parameters for non-adsorbed nuclides such as H-3, C-14, Tc-99, we introduced the variance-based sensitivity analysis methodology of the global sensitivity analysis. In the case of Silo type, the density of waste is highly sensitive to the total leakage quantity of all nuclides. Additionally, the initial nuclide concentration of H-3 was identified as another important parameter of H-3. On the other hands, the mass transport coefficient showed a high contribution in C-14 and Tc-99. In other types of disposal facilities, the leaking properties of H-3 are significantly affected by the amount of infiltration water. However, C-14 and Tc-99 were found to be more sensitive to the density of waste.
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