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        검색결과 991

        21.
        2023.10 구독 인증기관·개인회원 무료
        22.
        2023.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The bitterling (Cyprinidae, Acheilongnathinae) is a temperate freshwater fish with a unique spawning symbiosis with host mussels. Female bitterlings use their extended ovipositors to lay eggs on the gills of mussels through the mussel's exhalant siphon. In the present study, in April of 2020, we investigated spawning frequencies and patterns of three bitterling fish species in host mussel species in the Nakdong River basin (Hoecheon). During field surveys, a total of four bitterling and three mussel species were found. We observed bitterling's spawning eggs/larvae in the three mussel species: Anodonta arcaeformis (proportion spawned: 45.5%), Corbicula fluminea (12.1%), and Nodularia douglasiae (45.2%). The number of bitterlings’ eggs/larvae per mussel ranged from 1 to 58. Using our developed genetic markers, we identified the eggs/ larvae of each bitterling species in each mussel species (except for A. macropterus): A. arcaeformis (spawned by Acheilognathus yamatsutae), C. fluminea (A. yamatsutae and Tanakia latimarginata), and N. douglasiae (A. yamatsutae, Rhodeus uyekii, and T. latimarginata). Approximately 57.6% of N. douglasiae mussel individuals had eggs/ larvae of more than one bitterling species, suggesting that interspecific competition for occupying spawning grounds is intense. This is the first report on bitterling’s spawning events in the Asian clam C. fluminea from Korea; however, it should be ascertained whether bitterling’s embryo undergoes successful development inside the small mussel and leaves as a free-swimming juvenile. In addition, the importance of its conservation as a new host mussel species for bitterling fishes needs to be studied further.
        5,200원
        23.
        2023.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        ATP luminescence measurements (using Relative Light Units, RLU) has been used to assess the levels of bacterial contamination on the surfaces of various materials. However, not much is known about their suitability in assessing bacterial contamination on paper surfaces. This study was conducted to evaluate the feasibility of using ATP luminometers in measuring levels of bacteria contamination on paper surfaces. The three ATP luminometers studied were Clean-Q, smart PD-30, and 3M™ Clean-Trace™ LM1 manufactured by different companies. There were some differences in RLU results among the three ATP luminometers when they were tested with different concentrations of Micrococcus luteus cell suspension. 106 - 107 cells were required in order to effectively detect Bacillus subtilis, Escherichia coli, and Micrococcus luteus on the surfaces of A4 printing sheets (100 cm2) when using the three ATP luminometers. The sizes and physical properties of surface areas varied slightly among the swabs used for the three ATP luminometers. Concentration-specific measurements (RLU) of M. luteus taken from the surfaces of six kinds of paper (fine print paper, medium print paper, ground paper, newsprint paper, practice paper, tracing paper) were possible using the smart PD-30 and LM1 ATP luminometers. ATP detection values of M. luteus varied among the six types of paper. The highest ATP detection values were found on the surfaces of tracing paper. If the RLU value is recorded at the level of 1000, this could indicate a very high bacterial contamination level of 105 to 106 CFU/4 cm2.
        4,000원
        24.
        2023.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        As the capacity of renewable power generation facilities rapidly increases, the variability of electric power system and gas turbine power generation is also increasing. Therefore, problems may occur that require urgent repair while the gas turbine rotor is stopped. When the gas turbine rotor turning is stopped and then restarted, if the turning period is not appropriate, severe vibration may occur due to rotor bending. As a result of the experiment, it was confirmed that normal operation is possible when the gap data measured at the start of rotor turning after maintenance work is similar to the existing value. And the vibration value at the start of rotor turning was lower as the rotor temperature was lower or the stop period was shorter.
        4,000원
        25.
        2023.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigated the species composition and bycatch status of fishes by fyke net between June and November 2020 in Asanho lake and Chungjuho lake. During the survey period, the catches in Asanho lake were identified as 2,931 individuals of 16 species from a total of six families and in Chungjuho lake were identified as 1,645 individuals of 14 species from a total of eight families. The dominant species in Asanho lake was Erythroculter erythropterus which accounted for 59.6% of the the total number of individuals and 40.5% of the total biomass caught. The dominant species in Chungjuho lake was Lepomis macrochirus which accounted for 48.2% of the the total number of individuals and Erythroculter erythropterus which accounted for 60.2% of the total biomass caught. The bycatch rates of non-commercial species in Asanho lake and Chungjuho lake were 77.0% and 82.6%, respectively. As a result of analyzing the frequency distribution of the total length of Carassius auratus and Siniperca scherzeri, which were the dominant species among commercial species, the bycatch rate of small individuals was 87.1%, and 42.7%, respectively.
        4,000원
        26.
        2023.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The aim of this study was to compare the antioxidant activities and functional contents of Korean conventional and Chinese seed gingers from the Jeollabuk-do Wanju and Chungcheongnam-do Seosan regions. Ginger samples were subjected to steaming treatments for different durations (2–8 h) at 121oC using an autoclave. The antioxidant activity was evaluated by measuring total polyphenol and flavonoid contents and ABTS and DPPH radical scavenging activities, while functional ingredient contents were analyzed for gingerols and shogaols. The results showed that Wanju conventional seed ginger (WO-2) had the highest total polyphenol (85.24 mg GAE/g) and flavonoid (98.14 RE/100 g) contents, surpassing that of the control in all steamed groups at 6 h. ABTS radical scavenging activity showed a strong correlation with total polyphenol and flavonoid contents. The control groups indicated that Korean conventional seed ginger had 1.0–1.3 times higher gingerol contents compared to Chinese seed ginger. Furthermore, the content of shogaols, considered major functional ingredients, increased significantly with longer steaming durations, reaching the highest content (1,793 mg/kg) at 8 h, which was 1.0–1.8 times higher in Korean conventional seed ginger than that in Chinese seed ginger. These experiments provide valuable data supporting the excellence of Korean conventional seed ginger in the future.
        4,000원
        27.
        2023.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study analyzed the chemical characteristics and physiological activity of five kinds of fresh vegetables produced in trees in early spring and tried to use them as basic data for wild vegetable producers and processed food manufacturers using wild vegetables. The crude protein, minerals, ascorbic acid, folate, total phenol, total flavonoid, DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity and ACE (angiotensin converting enzyme) inhibitory activity were determined. Five spring wild vegetables contain high protein and phosphorus, indicating that they are useful food ingredients as sources of protein and phosphorus. Vitamin C content was high in R. venicifera and C. sinensis shoots, and in particular, R. venicifera and A. cortex shoots have high folic acid (folate) contents of 1,903.91 ug% and 1,525.35 ug%, respectively, which is considered a good food for folic acid intake in spring. The total phenol content was between 0.52% and 1.27%, and it was the highest in C. sinensis of 1.27%, followed by the order of R. venicifera, A.cortex, K.pictus, and A. elata, which tended to be consistent with the total flavonoid content. As for DPPH radical scavenging ability, C. sinensis (55.93%) showed the highest activity, and ACE inhibitory activity showed the highest activity in A. cortex (88.04%).
        4,000원
        28.
        2023.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The main factor of biodiversity decline in major biological populations around the world is invasion of alien species. To protect native species, it is necessary to manage alien species. Recently, to eradicate ecosystem disturbance caused by alien species in Korea, many efforts have been made to capture individuals using nets and purchase captured individuals. However, there is no standard for classifying species due to the form of nest site or external characteristics of eggs of freshwater turtles. Thus, Mauremys reevesii eggs might be discarded due to mistaking as eggs of alien turtles. Based on more data, this study aims to compare and analyze external differences among eggs of Trachemys scripta elegans, Pseudemys concinna, and M. reevesii and use them as reference materials in the process of eradicating alien turtles. This study measured characteristics of eggs of the three turtle species. As a result of comparison, all variables of external characteristics of alien turtles and M. reevesii eggs showed significant differences. The shape of egg was also different, with eggs of T. scripta elegans and P. concinna showing a bicone shape and those of M. reevesii showing an ellipsoid shape. In conclusion, based on results of previous studies and the present study, eggs of M. reevesii, T. scripta elegans, and P. concinna are different in shape and structure. Thus, it is possible to distinguish between M. reevesii and invasive alien turtle using their eggs.
        4,000원
        31.
        2023.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 한국산 맵시벌과 3종 (운문점박이납작맵시벌, 잎말이나방살이뭉툭맵시벌, 안경꼬마자루맵시벌)의 새로운 숙주를 보고하고 자 한다. 새로운 숙주는 각각 자나방과, 잎말이나방과, 풀명나방과에 속하며, 이 중 자나방과와 풀명나방과는 각각 쌍점박이납작맵시벌속, 안경꼬 마자루맵시벌속의 숙주로써 처음으로 기록된다. 여기에 맵시벌과 3종의 간략한 특징과 우화된 표본의 사진, 숙주의 성충 사진을 제공하였다.
        4,000원
        33.
        2023.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study aims to measure sedimentation status change with the changes in internal pressure for dry chemical extinguishers of various use periods and analyze the suitability of the fire extinguishers' performance criteria. When the internal pressure of the fire extinguisher is 0%, 2 out of 10 new dry chemical powders for the 5 elapsed years were noted to be suitable, including 3 recycled dry chemical powders with 5 elapsed years that were found eligible. One out of 10 new dry chemical powders for 10 elapsed years was shown as suitable. Also, one new dry chemical powder for 13 elapsed years was suitable. When the internal pressure of the fire extinguisher was 50%, all 10 out of 10 new dry chemical powders for 5 years, recycled one with 5 elapsed years, and a new one with 10 elapsed years were found to be suitable, while 9 new dry chemical powders for 13 years were shown as suitable. When the internal pressure of the fire extinguisher was normal, new ones with 5 elapsed years, recycled ones with 5 elapsed years, new ones with 10 elapsed years, and new ones with 13 elapsed years were all 10 out of 10 samples noted as suitable. In summarizing the experiment results, it was found that the sedimentation status, one of the fire extinguisher's physical properties experiments, affects the fire extinguisher's performance criteria rather than the change with use periods.
        4,000원
        35.
        2023.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 우울에 효과가 입증된 국내 자생 식물 9종(배초향, 적송, 강황, 생강, 산미나리씨, 불 수감, 황칠, 탱자, 쥐오줌풀) 을 선정하여 각각의 향기 성분 분석결과를 기반으로 9종 정유를 조합하여 항 산화(DPPH, ABTS), 세포독성(MTS), 항염(Nitric oxide)실험을 수행하였다. 향기성분 분석결과 조합오일 에서 기연구된 우울완화 효과 성분인 DL-Limonene(38.44%), g-Terpinene(8.9%), Estragole(5.18%), a-Pinene(1.73%) 등이 동정되었다. 항산화 활성인 DPPH 라디칼 소거능은 75.4%, ABTS 라디칼 소거능은 74.04%을 보였으며, 세포독성이 확인되지 않은 5uL/ml의 농도에서 NO 생성 저해능은 33.14%로 나타났 다. 이를 통하여 국내 블렌딩 정유의 우울증의 개선 또는 예방에 대한 효과를 검증하고 더불어 과학적 효능 과 성분 연구가 상호 협력적으로 이루어져 우울증적 증상 개선 유무를 확인 할 수 있는 기초자료로 제공하 고자 한다.
        4,000원
        36.
        2023.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        송충살이고치벌아과의 Aleiodes의 미기록종 4종(A. lipwigi, A. guidaae, A. subemarginatus, A. caprinus)을 국내 최초로 보고한다. 본 연구에 선 종의 동정을 위한 진단, 분포, 삽화 및 DNA 바코드 서열을 제공한다.
        4,000원
        37.
        2023.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        깡충좀벌과에 속하는 Neastymachus japonicus (Tachikawa,1970)와 Boucekiella depressa Hoffer, 1954 2종을 한국에서 처음으로 보고한다. 본 종의 기술, 분포, 삽화를 수록한다
        3,000원
        38.
        2023.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        광택집나방과의 국내 미기록 2종인 큰광택집나방(Argyresthia subrimosa Meyrick)과 황갈광택집나방(Argyresthia umbrina Liu, Wang et Li)을 보고한다. 큰광택집나방은 서로 멀리 떨어진 울릉도와 제주도 두 곳에서 발견되었다. 두 지역에서의 큰광택집나방 개체군을 외형 및 생식기 특징으로 비교하였다. 황갈광택집나방이 모식산지인 중국 이외 지역에서 발견된 것은 처음이다. 두 종의 외형 및 생식기 특징을 사진과 함께 기술하 였다.
        4,000원
        39.
        2023.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Phaedrotoma속은 주로 과실파리과, 혹파리과, 물가파리과, 꽃파리과, 똥파리과, 초파리과의 유충에 기생을 하는 고치벌로 한국에는 12종이 기록되어 있다. 본 조사연구 결과로 Phaedrotoma rugulifera와 Phaedrotoma vermiculifera 2종을 국내 최초로 보고한다. 이들의 표본은 쓸어잡기로 채집되었다. 두 종의 기술과 진단형질도판을 수록한다.
        4,000원
        40.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        There has been increased interest in lignans due to their potential effect in reducing the risk of developing several diseases. To evaluate lignan contents, sensitive and accurate methods should be developed for their quantification in food. The present study aimed to validate a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the quantification of 5 lignans: lariciresinol (Lar), matairesinol (Mat), pinoresinol (Pin), secoisolariciresinol (Seco), and syringaresinol (Syr). The validation included selectivity, linearity, recovery, accuracy, and precision. The method was proved to be specific, with a linear response (R2≥0.99). The limits of detection were 0.040~0.765 μg/100 g and the limits of quantification were 0.114~1.532 μg/100 g. Recoveries were 90.588~109.053% for black sesame powder. Relative standard deviations of repeatability and reproducibility were below 5%. Total lignan contents of roasted coffee bean, oat, and blacksoy bean were 105.702 μg/100 g, 78.965 μg/100 g, and 165.521 μg/100 g, respectively. These results showed that LC-MS/MS analysis would be effective in producing acceptable sensitivity, accuracy, and precision in five lignan analyses.
        4,000원
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