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        검색결과 2,890

        62.
        2023.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 후박나무 용기묘를 대상으로 전광, 35%, 55%, 75% 차광수준에 따른 생장 특성 및 생리적 반응을 알아보고자 실시하였다. 후박나무 묘목은 차광 시 상대적으로 지상부의 생장특성을 보여주는 지표들이 높은 경향을 보였으며, 전광에서는 뿌리와 관련된 지표인 뿌리건중비, 뿌리생장에 서 유의적으로 높은 경향을 보였다. 또한, 전광에서의 낮은 광보상점과 높은 순양자수율은 이미 후박나무가 내음성을 가지고 있고, 광이 부족한 환경에 노출된 차광처리구들에서 암호흡량의 감소, PIABS 및 SFIABS의 증가로 광합성 기구의 활력을 효율적으로 증가시키는 것을 알 수 있다. 한편, 전광은 지상부 비율의 증가, 낮은 T/R율과 가장 높은 순광합성속도를 보여 광합성으로 합성되는 탄수화물이 지상부 뿐만 아니라 지하부의 생장 역시 증가시킨 것을 알 수 있는 결과였다. 따라서 후박나무 용기묘는 전광조건에서 생장 및 생리적 특성이 가장 양호한 경향을 보였다.
        4,200원
        63.
        2023.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study aimed to investigate the effect of a coating agent on pork storage. Pork was coated with a coating agent containing sodium carboxymethyl cellulose (CMC) and mandarin peel powder (M). The treatments were divided into control, a 0.1% CMC treatment, and a 0.1% CMC +5% M treatment, and pH, color, 2-thiobarbituric acid reactive substances (TBARS), volatile basic nitrogen (VBN), and the number of viable cell counts were measured. In the case of redness (a), it was found that the reduction over the storage period was less in the 0.1% CMC + 5% M treatment than in the control and the 1% CMC treatment. When stored at 4oC and 25oC, TBARS of pork tended to increase during the storage period, followed by control, 0.1% CMC treatment, and 0.1% CMC + 5% M treatment, indicating that lipid oxidation was most suppressed in pork coated with mandarin peel powder. As a result of measuring the VBN of pork stored at 4oC and 25oC, the 0.1% CMC + 5% M treatment showed lower values than the control and 0.1% CMC treatment. When the film-coated pork was stored at 4oC, the number of viable cell counts in the 0.1% CMC +5% M treatment area was 7.13±0.96 log CFU/g on the 12th day of storage, delaying the growth of viable cell counts for approximately 3 d more than other treatments. Therefore, coating pork with a film containing CMC and mandarin peel powder has been confirmed to delay the increase in the number of viable cell counts while reducing the quality change during pork storage, which is an effective alternative to improving the storage of fresh food as an edible film.
        4,000원
        64.
        2023.04 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Lactococcus garvieae is a Gram-positive cocci that has been known to be a fish pathogen, and considered as a low virulence organism rarely associated with human infection. We report a case of acute cholangitis with common bile duct (CBD) stone and bacteremia by L. garvieae bacteremia in a 70-year-old male. The patient presented with epigastric pain and was diagnosed with two CBD stones. Blood culture obtained prior to empiric antimicrobial therapy with ceftizoxime sodium showed growth with Escherichia coli and L. garvieae. The bacteria were confirmed by matrix-assisted desorption/ionization time-of-flight mass spectrometry. Initial attempt at endoscopic biliary drainage failed, and the patient underwent percutaneous transhepatic biliary drainage and subsequent stone removal. He occasionally ingested raw fish and had a history of gastric ulcer with acid suppression therapy, which could be possible risk factors for L. garvieae infection. This is the first case of L. garvieae bacteremia in acute cholangitis.
        4,000원
        70.
        2023.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We investigated the spatial distribution of heterotrophic bacteria associated with different water masses in the northern East China Sea (ECS) in summer. The surface water masses were divided into the Changjiang Diluted Water (CDW) and high salinity water (HSW). In the CDW region, the concentrations of dissolved inorganic nitrogen (DIN) and chlorophyll-a (Chl-a), and micro Chl-a contribution were high; and bacterial abundance (BA) and ciliate abundance (CA) were also high. In the HSW region with relatively low DIN concentrations, Chl-a concentration and micro Chl-a contribution were low, but pico Chl-a contribution was increased compared to those in the CDW region. BA did not show any significant difference from the CDW region, but CA was decreased. BA showed a positive correlation with Chl-a concentration in the CDW region; however, it did not show a significant correlation with Chl-a concentration in the HSW region. The ratio of bacterial carbon biomass/phytoplankton carbon biomass was exponentially increased with a decrease in the Chl-a concentration. Compared to the past (1990-2000s), the surface phosphate concentrations and the size of dominant phytoplankton have recently decreased in the ECS. Considering this trend of nutrient decrease and miniaturization of the phytoplankton, our results indicate that changes in the strength of the oligotrophic water mass could alter the function of the microbial food web.
        4,300원
        71.
        2023.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Recently, Korean government has introduced Multi Metric Indices (MMI) using various biocommunity information for aquatic ecosystem monitoring and ecosystem health assessment at the national level. MMI is a key tool in national ecosystem health assessment programs. The MMI consists of indices that respond to different target environmental factors, including environmental disturbance (e.g. nutrients, hydrological and hydraulic situation of site etc.). We used zooplankton community information collected from Korean lakes to estimate the availability of candidate zooplankton MMI indices that can be used to assess lake ecosystem health. First, we modified the candidate indices proposed by the U.S. EPA to suit Korean conditions. The modified indices were subjected to individual index suitability analysis, correlation analysis with environmental variables, and redundancy analysis among indices, and 19 indices were finally selected. Taxonomic diversity was suggested to be an important indicator for all three taxonomic groups (cladoceran, copepod, rotifer), on the other hand, the indices using biomass for large cladocerans and copepods, while the indices using abundance were suggested for small cladocerans and rotifers.
        4,500원
        72.
        2023.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to investigate the vertical distribution and vascular plants in the Gakho mountain. Form the results of three field surveys from May 2022 to September 2022, a total of 478 total taxa, representing 426 species, 11 subspecies, 35 varieties, four forms, and two hybrids were identified, which were categorized in 282 genera and 94 families. We identified the elevational distribution ranges of 398 taxa of vascular plants. Among them, 19 taxa were endemic to Korea, one taxon was identified as a rare plant. The floristic target plants amounted to 72 taxa, specifically two taxa of grade V, two taxa of grade IV, 16 taxa of grade III, 27 taxa of grade II, and 25 taxa of grade I. Further, 71 taxa were identified as northern lineage plants. A total of 19 taxa of alien plants were identified, with a Naturalized Index of 4.0%, an Urbanization Index of 6.6%, and three plants that disturbed the ecosystem. The result of analyzing the pattern of species richness showed a reversed hump shape with minimum richness at midhigh elevation. A cluster analysis showed a high degree of similarity between adjacent elevation sections that are geographically adjacent with similar habitat environments. Warmth index in the Gakho mountain ranged from 57.2°C · month to 84.2°C · month. Our results provide basic data on vascular plants and valuable information on elevational distribution ranges of current plant species in the Gakho mountain, which could serve as a baseline for comparison of the shifts in elevation under future climate change.
        6,900원
        74.
        2023.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to analyze the physicochemical properties by mixing ratio of soybean and peanut protein to secure basic data for developing alternative protein foods. As a result of analyzing the protein molecular weight pattern, it was confirmed that the specific molecular weight was affected by the soybean and peanut protein mixture. The content of glutamic acid, aspartic acid, arginine, glycine, serine, alanine, and tyrosine among nonessential amino acids was higher as the mixing ratio of peanut protein to soy protein was higher. However, the higher the peanut protein mixing ratio, the lower the water absorption capacity. Based on the results of this study, further studies, such as selecting soybean and peanut cultivars for determining the optimal mixing ratio of soybean and peanut protein and processing methods to improve physical properties, are necessary
        4,000원
        75.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        테프라연대학은 광역테프라를 연대측정과 층서대비에 이용하는 연구이다. 광역 테프라층은 층서적 건층으로 사 용될 수 있기 때문에 제4기지질학과 고고학 분야에서 매우 중요하다. 이 논평에서는 테프라의 동정 방법과 연대측정 방법에 대해 정리하였다. 또한 한반도의 육상퇴적층에서 발견되는 광역테프라층의 종류와 산출 특성에 대해 정리하였고, 광역테프라층의 지질학적 활용 방법과 한계점에 대해서도 토의하였다. 지금까지 한반도 육상의 고토양층, 해안단구 퇴 적층, 호수퇴적층에서는 일본 큐슈 기원의 AT와 Ata, Kb-Ks 테프라가 발견되었다. 또한 공식적으로 발견되지는 않았지 만 Aso-4 테프라도 발견될 가능성이 높은 것으로 판단된다. 광역테프라층은 제4기 퇴적층, 특히 방사성탄소연대측정의 범위를 넘는 5만년 이상 퇴적층의 연대측정과 층서대비에 유용하며, 활성단층의 연대측정과 화산재해에 대한 대응책 마 련에도 유용한 정보를 제공한다. 하지만 테프라층을 지질학적으로 이용하기 위해서는 퇴적학적 연구를 통해 일차퇴적 여부에 대한 확인이 필요하다.
        4,200원
        76.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Thermal protection systems (TPS) are a group of materials that are indispensable for protecting spacecraft from the aerodynamic heating occurring during entry into an atmosphere. Among candidate materials for TPS, ceramic insulation materials are usually considered for reusable TPS. In this study, ceramic insulation materials, such as alumina enhanced thermal barrier (AETB), are fabricated via typical ceramic processing from ceramic fiber and additives. Mixtures of silica and alumina fibers are used as raw materials, with the addition of B4C to bind fibers together. Reaction-cured glass is also added on top of AETB to induce water-proof functionality or high emissivity. Some issues, such as the elimination of clumps in the AETB, and processing difficulties in the production of reusable surface insulation are reported as well.
        4,000원
        77.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        금속의 취성화는 수소와 접촉하는 구조물을 안정적으로 설계하는데 있어서 큰 문제가 되어왔다. 본 논문에서는 분자동역학 해석을 통해 균열선단 주변에 모인 수소원자들이 전위 이동 현상을 억제하고, 이로 인해 벽개 파괴 현상이 발생하는 것을 확인하였다. 다양한 수소 농도, 하중 속도, 수소 확산 속도 등을 바꾸어가며 분자동역학 해석을 수행하였고, 이에 따른 수소 취성화를 최소화시킬 수 있는 조건들을 조사하였다. 분자동역학 해석 결과는 기존의 실험결과와 잘 일치하였으며 이를 바탕으로 수소 취성화 현상을 정량화하여 평가하였다.
        4,000원
        78.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Through sample-size-based rarefaction analyses, we tried to suggest the appropriate degree of sample concentration and sub-sample extraction, as a way to estimate more accurate zooplankton species diversity when assessing biodiversity. When we collected zooplankton from three reservoirs with different environmental characteristics, the estimated species richness (S) and Shannon’s Hʹ values showed different changing patterns according to the amount of sub-sample extracted from the whole sample by reservoir. However, consequently, their zooplankton diversity indices were estimated the highest values when analyzed by extracting the largest amount of sub-sample. As a result of rarefaction analysis about sample coverage, in the case of deep eutrophic reservoir (Juam) with high zooplankton species and individual numbers, it was analyzed that 99.8% of the whole samples were represented by only 1 mL of sub-sample based on 100 mL of concentrated samples. On the other hand, in Soyang reservoir, which showed very small species and individual numbers, a relatively low representation at 97% when 10 mL of sub-sample was extracted from the same amount of concentrated sample. As such, the representation of sub-sample for the whole zooplankton sample varies depending on the individual density in the sample collected from the field. If the degree of concentration of samples and the amount of subsample extraction are adjusted according to the collected individual density, it is believed that errors that occur when comparing the number of species and diversity indices among different water bodies can be minimized.
        4,200원
        79.
        2022.12 구독 인증기관 무료, 개인회원 유료
        붕어(무게 28.1±3.7 g, 길이 10.0±1.0 cm)에 0, 2.0×104, 2.0×105, 2.0×106, 2.0×107 CFU/ml의 Aeromonas hydrophila를 주사 후 2주간 실험을 실시하였다. A. hydrophila로 인위감염한 Carassius carassius의 2주 뒤 반수치사농도는 19.776×105 CFU/ml이었다. 혈액학적 지표에서는 A. hydrophila에 의해 혈색소와 적혈구 수가 유의하게 감소한 반면, 적혈구 용적은 유의적 변 화가 없었다. 마그네슘, 칼슘과 같은 혈장 무기 성분은 유의적으로 감소하였다. 유기 혈장 성분 에서 A. hydrophila 인위감염에 의해 혈장 포도당과 콜레스테롤이 유의하게 증가한 반면, 총 단 백질은 유의하게 감소하였다. 혈장 효소 성분인 ALP는 A. hydrophila 인위감염에 의해 유의하 게 증가하였다. 본 연구의 결과는 C. carassius에 대한 A. hydrophila의 인위감염이 치명적인 병원성 세균으로 혈액학적 성상 및 혈장 성분에 유의한 생리학적 변화를 유도하였음을 의미 한다.
        4,000원
        80.
        2022.12 구독 인증기관 무료, 개인회원 유료
        붕어(무게 42.4 ± 9.0 g, 길이 15.0 ± 1.0 cm)를 96시간 동안 0, 5, 10, 20, 40 및 80 mg Zn2+/l의 수 인성 아연에 노출시켰다. 수인성 아연에 노출된 붕어의 96시간 반수치사농도(LC50)는 51.58 mg Zn2+/l였다. 혈액학적 지표에서 48시간에 40 mg Zn2+/l 농도에서 RBC 수치가 유의하게 감소 한 반면, 헤마토크릿은 아연 노출에 의해 유의하게 증가하였다. MCV (μl)와 MCH (pg)는 40 mg Zn2+/l 농도에서 48시간에 유의하게 증가하였다. 칼슘, 마그네슘, 포도당, 콜레스테롤, 총 단백질 및 ALT와 같은 혈장 성분은 아연 노출에 의해 크게 변화되었다. 본 연구의 결과는 붕어에 대한 아연 노출이 독성으로서 혈액학적 매개변수 및 혈장 성분의 유의한 생리학적 변화를 유발함을 시사한다.
        4,000원
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