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        검색결과 4,101

        301.
        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
        302.
        2022.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Acrylonitrile–butadiene–styrene (ABS) terpolymer was compounded with short carbon fiber (CF) and carbon nanotube (CNT) using a micro-extruder followed by the injection molding process. Composite samples were fabricated with loading ratios of 20 wt.% CF and 0.1, 0.5 and 1.0 wt.% of CNT. Mechanical, electrical, thermo-mechanical, thermal, melt-flow, and structural investigations of ABS-based composites were conducted by performing tensile, impact, hardness, and wear tests, conductive atomic force microscopy (AFM), dynamic mechanical analysis (DMA), thermal gravimetric analysis (TGA), melt flow rate test (MFR), scanning electron microscopy (SEM) characterization techniques, respectively. According to mechanical test data of resultant composites including tensile and impact test findings, CNT additions led to the remarkable increase in tensile strength and impact resistance for CF reinforced ABS composites. The formation of synergy between CNT nanoparticles and CF was confirmed by electrical conduction results. The conductive path in ABS/CF composite system was achieved by the incorporation of CNT with different loading levels. SEM micrographs of composites proved that CNT nanoparticles exhibited homogeneous dispersion into ABS matrix for lower loadings.
        4,300원
        303.
        2022.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Several countries, including Korea, are considering the direct disposal of spent nuclear fuels. The radiological safety assessment results published after a geological repository closure indicate that the instant release is the main radiation source rather than the congruent release. Three Safety Case reports recently published were reviewed and the IRF values of seven long-lived radionuclides, including relevant experimental results, were compared. According to the literature review, the IRF values of both the CANDU and low burnup PWR spent fuel have been experimentally measured and used reasonably. In particular, the IRF values of volatile long-lived nuclides, such as 129I and 135Cs, were estimated from the FGR value. Because experimental leaching data regarding high burnup spent nuclear fuels are extremely scarce, a mathematical modelling approach proposed by Johnson and McGinnes was successfully applied to the domestic high burnup PWR spent nuclear fuel to derive the IRF values of iodine and cesium. The best estimate of the IRF was 5.5% at a discharge burnup of 55 GWd tHM−1.
        4,200원
        304.
        2022.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Two tree frogs, Dryophytes suweonensis and Dryophytes japonicus, inhabiting Korea, are morphologically similar and share the same habitats. Therefore, they are identified mainly through their calls, especially for males. Dryophytes suweonensis is registered as an endangered (IUCN: EN grade) and protected species in South Korea. Thus, it is necessary to develop a method to rapidly identify and discriminate the two species and establish efficient protection and restoration plans. We identified significant genetic variation between them by sequencing a maternallyinherited mitochondrial 12S ribosomal DNA region. Based on the sequence data, we designed a pair of primers containing 7 bp differences for high resolution melting (HRM) analysis to rapidly and accurately characterize their genotypes. The HRM analysis using genomic DNA showed that the melting peak for D. suweonensis was 76.4±0.06°C, whereas that of D. japonicus was 75.0±0.05°C. The differential melt curve plot further showed a distinct difference between them. We also carried out a pilot test for the application of HRM analysis based on immersing D. suweonensis in distilled water for 30 min to generate artificial environmental DNA (eDNA). The results showed 1.10-1.31°C differences in the melting peaks between the two tree frog samples. Therefore, this HRM analysis is rapid and accurate in identifying two tree frogs not only using their genomic DNA but also using highly non-invasive eDNA.
        4,000원
        305.
        2022.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        A compacted bentonite buffer is a major component of engineered barrier systems, which are designed for the disposal of high-level radioactive waste. In most countries, the target temperature required to maintain safe functioning is below 100°C. If the target temperature of the compacted bentonite buffer can be increased above 100°C, the disposal area can be dramatically reduced. To increase the target temperature of the buffer, it is necessary to investigate its properties at temperatures above 100°C. Although some studies have investigated thermal-hydraulic properties above 100°C, few have evaluated the water suction of compacted bentonite. This study addresses that knowledge gap by evaluating the water suction variation for compacted Korean bentonite in the 25–150°C range, with initial saturations of 0 and 0.22 under constant saturation conditions. We found that water suction decreased by 5–20% for a temperature increase of 100–150°C.
        4,000원
        306.
        2022.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        목적: 상분리가 일어나지 않는 실리콘하이드로겔 콘택트렌즈(silicone hydrogel contact lens, SH-CL) 제조에 적합한 실리콘 모노머의 구조를 알아보고자 한다. 방법 : HEMA(2-hydroxyethyl methacrylate)와 세 종류의 실리콘 모노머, TRIM[3-(trimethoxysilyl)propyl methacrylate, Aldrich], TEMA[2-(trimethylsilyloxy)ethyl methacrylate, TCI], TMMA[(trimethylsilyl) methacrylate, Aldrich]를 활용하여 완전몰드로 SH-CL를 제조하였다. 함수율과 UV-VIS spectrophotomter 를 이용한 광투과율, TGA 분석을 통한 열적안정성 등의 물리적 특성과 FT-IR 분석을 통한 화학적 특성을 알아 보았다. 결과 : 동일한 양의 TRIM, TEMA, TMMA를 사용하여 제작한 SH-CL의 광투과율은 각각 92%, 86%, 80%로 측정되었으며, 함수율은 TRIM을 사용한 SH-CL에서 39.3%로 가장 높게 나타났다. FT-IR 분석 결과 세 종류의 SH-CL 모두 silicone monomer와 HEMA의 중합반응이 잘 이루어졌음을 확인할 수 있었고, TGA 분석을 통해 TRIM monomer의 sol-gel 반응 유무를 확인할 수 있었다. 결론 : Sol-gel 반응에 적합한 구조를 가지고 있어 상분리가 일어나지 않아 투명하고, Si에 극성 작용기인 methoxy기가 연결되어 있는 TRIM monomer가 SH-CL 제조에 적합한 구조임을 확인할 수 있었다.
        4,000원
        307.
        2022.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        네덜란드 연극 Elckerlijc를 번역한 􋺷만인􋺸은 중세 교회의 전례에서 종교적 주제와 극적인 모티프의 전통을 따른다. 순결, 유혹, 회개, 구원과 같은 도덕극 의 종교적인 특징은 􋺷만인􋺸에서 재현된다. 이 작품은 성례전을 중심으로 한 가 톨릭의 가르침을 극화하고, 성경 본문과 교리를 교훈적인 목적으로 사용하여 만 인의 마지막 여정을 향한 순례를 통해 기독교 세계관을 공유한다. 􋺷만인􋺸은 은 혜를 의지하고 은혜의 상태에서 선행을 함으로써 죽음의 순간에 세상의 죄가 없는 한 영혼은 구원받을 수 있다고 가르친다. 본고는 연극적 취지와 관련하여 당대의 종교적 사상의 범주를 간략히 살펴보고, 작품이 그 시대의 종교적 담론 을 어떻게 반영하고 드러내는지 분석한다. 특히 이 연구는 죽음과 구원에 관한 주인공의 영적 자기 인식이 삶의 마지막 순례에서 중세 가톨릭 교리와 도덕 규 범의 종교적 행위 안에서 드러나는 방식의 다양성을 고찰한다. 또한, 종교개혁 전후 중세 영국의 종교적 맥락 안에서 우화적인 인물들을 통한 서사와 교훈적 전략을 분석한다.
        5,500원
        308.
        2022.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Grapevine leaf rust (GLR) caused by Phakopsora euvitis results in the reduction of fruit quality and yield loss in grape production. The purpose of this study was to investigate the expression of genes related with defense responses in the grapevines infected with rust pathogens. In two genotypes of Ampelopsis species inoculated with P. euvitis, the real-time PCR with RNAs was performed to investigate transcripts levels of nine defense-related genes, including pathogenesis-related 1 (PR1), β-1,3glutannase (Glu), chitinase (Chi), superoxide dismutases (SOD), glutathione peroxidase (GPX), phenylalanine ammonia lyase (PAL), chalcone synthase (CHS), stilbene synthase 1 (STS1), and resveratrol O-methyltransferase (ROMT). All tested genes were upregulated in YG11030 as well as YG10075, while mostly the expression of genes was higher in YG10075 than that in YG11030. Glu and STS showed significantly high expression in YG10075 than in YG11030. Expression of ROMT was upregulated in YG11030 and downregulated in YG10075 at 24 hours after inoculation. The differential expression pattern of the tested genes seems to be related with the defense responses, considered to be involved in plant-resistant responses against the infection by P. euvitis, and further studies on resistant responses based on the expression of genes would provide valuable information in breeding grapes resistant to diseases.
        4,000원
        309.
        2022.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        목적: 국민건강영양조사 제7기(2016-2018) 원시자료를 이용하여 황반변성에 영향을 줄 수 있는 만성질환을 파악 하고자 수행되었다. 방법 : 국민건강영양조사 제7기(2016-2018) 자료 중 40세 이상의 성인 중에 황반변성 진단여부에 응답한 4,356명의 대상으로 만성질환과의 관계를 분석하였으며, p<0.05인 경우 유의한 것으로 판단하였다. 결과 : 황반변성은 연령에 따라 유병률이 높아졌는데, 연령과 관계된 만성질환 중 심근경색증에서만 유의한 결 과를 얻을 수 있었다. 또한, 심근경색증의 위험요인인 이상지질혈증과 이상지질혈증을 일으키는 고콜레스테롤혈증 도 황반변성과 관계가 있는 것으로 나타났다. 결론 : 황반변성은 연령과 관련된 만성질환 중 심근경색증, 이상지질혈증, 고콜레스테롤혈증과 관련이 있음을 확인하였다.
        4,000원
        310.
        2022.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The ability to determine the sex of bovine embryos before the transfer is advantageous in livestock management, especially in dairy production, where female calves are preferred in milk industry. The milk production of female and male cattle benefits both the dairy and beef industries. Pre-implantation sexing of embryos also helps with embryo transfer success. There are two approaches for sexing bovine embryos in farm animals: invasive and non-invasive. A non-invasive method of embryo sexing retains the embryo’s autonomy and, as a result, is less likely to impair the embryo’s ability to move and implant successfully. There are lists of non-invasive embryo sexing such as; Detection of H-Y antigens, X-linked enzymes, and sexing based on embryo cleavage and development. Since it protects the embryo’s autonomy, the non-invasive procedure is considered to be the safest. Invasive methods affect an embryo’s integrity and are likely to damage the embryo’s chances of successful transformation. There are different types of invasive methods such as polymerase chain reaction, detection of male chromatin Y chromosomespecific DNA probes, Loop-mediated isothermal amplification (LAMP), cytological karyotyping, and immunofluorescence (FISH). The PCR approach is highly sensitive, precise, and effective as compared to invasive methods of farm animal embryonic sexing. Invasive procedures, such as cytological karyotyping, have high accuracy but are impractical in the field due to embryonic effectiveness concerns. This technology can be applicable especially in the dairy and beef industry by producing female and male animals respectively. Enhancing selection accuracy and decreasing the multiple ovulation embryo transfer costs.
        4,000원
        311.
        2022.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The leaves of Allium victorialis (AV) are known an edible perennial herb, which has been used in Korean traditional medicine. However, the beneficial pharmacological effects of AV extracts (AVE) on the antioxidant activity and atopic dermatitis (AD) have not been thoroughly examined. Therefore, the present study aims to investigate both antioxidant activity and anti-inflammatory effect of AVE on AD in vitro and in vivo. Antioxidant activity was evaluated by total polyphenol content and ferric reducing ability. AVE showed a level of polyphenol content and reducing power activity. The five-week-old BALB/c mice were used as an AD-like mouse model by treating them with 1-chloro-2, 4-dinitrobenzene (DNCB). Topical administration of AVE for 3 weeks to DNCB-treated mice significantly alleviated clinical skin lesion dermatitis severity and epidermal thickness. Histopathological analysis also demonstrated that AVE decreased eosinophil and mast cell infiltration into skin and ear tissue. These results suggest that topical application of AVE inhibits the development of AD-like skin lesion in mice by their antioxidant activity. Thus, AVE may be a potential therapeutic agent for AD.
        4,000원
        312.
        2022.06 구독 인증기관 무료, 개인회원 유료
        Mitochondrial genomes of three specimens of Gadus chalcogrammus Pallas 1,814 from Korea and Japan were completely analyzed by the primer walking method. They were 16,570~16,571 bp in length, each comprising 13 protein-coding genes, two ribosomal RNA genes, and 22 transfer RNA genes. Their gene orders were identical to those of conspecific specimens, but exhibited unique haplotypes. In the phylogenetic tree, the juvenile Korean and adult Japanese specimens were separated from the dominant clade composed of specimens from Japan, Korea, the Bering Sea, and the Arctic, including the adult Korean specimen.
        3,000원
        313.
        2022.06 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        Human intestinal flora is very diverse; with lactic acid bacteria (LAB) existing as part of the most vital gut microbes that improve host health. The application of LAB as a whole organism or its metabolite in the case of probiotic and bacteriocin respectively is extensive. Thus, the need to always bio-prospect for newer strains of LAB is essential. This study focused on isolating LAB from kunun-zaki and kindirmo, a fermented non-alcoholic beverage of non-dairy and dairy sources respectively, explored their physiological and biochemical properties, antibiotics sensitivity pattern and identified based on their 16S rRNA sequencing. A total of eighty isolates were selected sixty-six from kunun-zaki and fourteen from kindirmo in which 93.7% were bacilli and 6.3% were spherical in shape having 68.75% and 30% homofermentative and heterofermentative pathway respectively. All isolates have the ability to utilize glucose to produce lactic acid while their tolerance to pH 3 and salt concentration at 2%, 4% and 6.5% varied widely. Thirty-four isolates based on their physiological and biochemical properties were selected for molecular identification to ascertain their genera and species. Limosilactobacillus fermentum (68%); Lactiplantibacillus plantarum (6%) and Weissella confusa (3%) were confirmed species isolated. Thus, it was concluded that traditional fermented foods such as kunun-zaki and kindirmo are a good source to bio-prospect for LAB for product development, starter culture and probiotic study.
        4,800원
        314.
        2022.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        요통을 호소하는 환자에서의 자기공명영상 검사는 다른 영상 진단법에 비해 요추와 주변 조직에 대한 높은 대조도와 해상력, 다양한 영상면의 획득으로 해부학적 구조 파악과 다양한 척추 질환의 진단에 널리 활용되고 있다. 그러나 자기공명 영상 검사는 검사 시간이 길기 때문에 통증으로 협조가 되지 않는 환자들에게서 움직임에 의한 인공물을 유발하는 경우가 많아 검사 시간을 최소화하는 것이 중요하다. 이에 자기공명영상 검사 시간 단축을 위한 다양한 기법들이 개발되어 왔으며, 최근 높은 영상의 질을 유지하면서 검사 시간은 크게 줄이는 K-공간 기반 딥 러닝(K-space based Deep Learning, DL) 기법이 주목받고 있다. 본 연구는 요추 자기공명영상 검사에서 DL 기법의 유용성을 알아보기 위해 본원을 내원하여 척추 질환이 의심되는 환자를 대상으로 DL 기법 적용 전후 시상면 T2 강조 영상과 축상면 T2 강조 영상을 각각 획득하였으며, 신호대잡음비와 대조대잡음비, 영상 획득 시간, 전체적인 영상의 질 및 병변 진단 일치도를 비교 분석하였다. 연구 결과 영상의 질 향상과 검사 시간의 단축뿐만 아니라 빠른 영상 획득으로 움직임이나 호흡에 의한 인공물 또한 감소하는 것을 볼 수 있었다. 따라서 자기공명영상 검사에서 DL 기법 사용 시 진단적 가치가 보다 높은 영상을 제공하는 동시에 환자의 만족도를 높여 임상에서도 유용한 방법이 될 것으로 사료된다.
        4,000원
        318.
        2022.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Although various conventional approaches have been employed to reduce spasticity in neurological rehabilitation, only a few studies have shown scientific evidence for its effectiveness. Thus, we introduced a different concept (Ueda method) of rehabilitation therapy that can complement the limitations of conventional therapy. Objects: This study aimed to investigate the immediate effects of the application of the Ueda method on patients with spasticity after stroke via an electrophysiological study. Methods: We conducted a randomized double-blind pilot study in two rehabilitation hospitals involving 30 stroke patients who were randomly allocated to the Ueda (n = 15) and convention (n = 15) groups. Electromyographic data of six examined muscles in both upper extremities of all patients were recorded. The A-ApA index and activation ratios of upper extremity muscles were evaluated and compared between the groups to confirm post-intervention changes in upper-extremity flexor spasticity and flexion synergies. Repeated-measures analysis of variance was conducted to confirm the therapeutic effect (2 × 2) as a function of group (Ueda vs. convention) and time (pre-/post-intervention) on all outcome measures (p < 0.05). Results: In the Ueda group, the mean A-ApA index values differed significantly before and after the intervention (p = 0.041), indicating a weak evidence level; however, the effect size was medium (d = –0.503). The interaction effects of the A-ApA index between the Ueda and convention groups and between pre-intervention and post-intervention stages were significant (p = 0.012). The effect size was large (np 2 = 0.220). In the Ueda group, the activation ratios of the anterior deltoid fiber significantly decreased after the intervention in all reaching tasks. Conclusion: The Ueda method reduces upper-extremity flexor spasticity and changes its synergy in stroke patients and should be considered a rehabilitation therapy for spastic stroke patients.
        4,000원
        319.
        2022.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Natural environmental resources are considered a prospective source of microorganisms capable of producing biocatalysts with great potential in industrial areas. Arable soil fertilized with peat moss is a habitat for various microorganisms. The present research focused on the isolation and identification of hydrolase-producing bacteria that thrive at a broad temperature range. In this study, a total of 33 strains were isolated from arable soil fertilized with peat moss (Silla Garden in Busan, South Korea). The isolated bacteria were mesophiles and thermophiles with a wide temperature range. Taxonomic identification showed that the isolated strains belonged to 2 phyla, 5 families, 10 genera, and 24 species. Subsequently, the isolated strains were screened for hydrolase (amylase, lipase, and protease) activity. All isolates possessed activity of at least one enzyme and six bacterial isolates produced combined extracellular enzymes. Diversity of soil bacteria species in the present study suggest the potential of soil bacteria in the various industrial applications.
        4,000원
        320.
        2022.05 구독 인증기관·개인회원 무료
        Technetium-99 (99Tc) is a challenging radionuclide from presents many problems related to safe disposal. The measurement of 99Tc is of particular interest due to its high mobility, and the fact that it is a beta-emitter with a long half-life (t1/2=2.13×105 years) with long-term radiological effects[1]. As an isotopes of 99Tc, 99mTc has been widely applied for medical diagnosis and medical research. It is reported that the 99mTc has been used in 80% of diagnostic nuclear medicine procedures and almost 30 million examinations are conducted worldwide using this isotope. Because 99mTc has a short half-life of 6 h and decays to 99Tc, monitoring and safe disposal of 99Tc from human urine is very important, and concern is increasing every day as global use of 99mTc has increased by more than 4.5×1014 Bq per week and is increasing continuously[2]. However, the current methods for the detection of this radionuclide in such mdium are time consuming and can not satisfy for the low level urine sample analysis. In this work, a method for rapid determination of 99Tc in urine samples was developed. The sample was firstly pre-treated with K2S2O8 to decompose the organic matters combined with 99Tc in 0.5 mol·L−1 HNO3 medium at 100°C. Then the sample solution was loaded to a TEVA column (2 mL) for 99Tc separation and purification. The target element was finally measured by high resolution inductively coupled plasma mass spectrometry (HR-ICPMS). The developed analytical method was proved to be reliable and can be used to rapid determine low-level 99Tc in urine samples.