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        검색결과 821

        125.
        2021.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 플라즈마 발생 장치를 수경재배 시스템과 결합하여 상추를 재배하고 수확 후 플라즈마 활성수와 과산화수소 0, 3, 6% 농도에 침지 처리를 하여 생육량 및 바이오 활성 물질 함량을 비교하였다. 고농도의 과산화수소로 인하여 근권부 생체중이 저해되는 결과를 나타냈으며, 엽장과 근권부 생체중을 제외하고는 유의적 차이가 발생하지 않았다. 상추 지상부의 chlorogenic acid와 4-hydroxy3-benzoic acid, 4-hydroxy benzoic acid 그리고 지상부 총 페놀 함량은 과산화수소 6%에 서 유의적으로 가장 높았다. 하지만 근권부에서 측정된 이차 대사산물인 quercetin 및 근권부 총 페놀 함량은 과산화수소 처리구보다 플라즈마 활성수에서 유의하게 높았다. 과산화수소 처리 기간 동안 상추의 뿌리는 직접적인 피해를 받으며 괴사하였으나, 잎에서는 과산화수소 6% 처리에서 바이오 활성 물질이 증가하는 결과를 나타내었다. 플라즈마 활성수 처리 상추는 생리 장해가 발생하지 않았으며, 과산화수소 6% 처리와 유사한 양의 이차대사산물 증대 효과를 나타내었다. 또한, 뿌리의 바이오 활성 물질 함량이 가장 높았던 결과 등을 고려 할 때 근채류 및 엽채류의 수경재배에 플라즈마 기술을 적용할 시 작물의 바이오 활성 물질 함량을 증대시키는 데 효과적일 것으로 판단된다.
        4,000원
        126.
        2021.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Powder quality, including high flowability and spherical shape, determines the properties of additively manufactured products. Therefore, the cheap production of high-quality powders is critical in additive manufacturing. Radio frequency plasma treatment is an effective method to fabricate spherical powders by melting the surface of irregularly shaped powders; in the present work, mechanically milled Zr powders are spheroidized by radio frequency plasma treatment and their properties are compared with those of commercial Zircaloy-2 alloy powder. Spherical Zr particles are successfully fabricated by plasma treatment, although their flowability and impurity contents are poorer than those of the commercial Zircaloy-2 alloy powder. This result shows that radio-frequency plasma treatment with mechanically milled powders requires further research and development for manufacturing low-cost powders for additive manufacturing.
        4,000원
        127.
        2021.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A pregnancy diagnosis is an important standard for control of livestock’s reproduction in paricular dairy cattle. High reproductive performance in dairy animals is a essential condition to realize of high life-time production. Pregnancy diagnosis is crucial to shortening the calving interval by enabling the farmer to identify open animals so as to treat or re-breed them at the earliest opportunity. MicroRNAs are short RNA molecules which are critically involved in regulating gene expression during both health and disease. This study is sought to establish the feasible of circulating miRNAs as biomarkers of early pregnancy in cattle. We applied Illumina small-RNA sequencing to profile miRNAs in plasma samples collected from 12 non-pregnant cows (“open” cows: samples were collected before insemination (non-pregnant state) and after pregnancy check at the indicated time points) on weeks 0, 4, 8, 12 and 16. Using small RNA sequencing we identified a total of 115 miRNAs that were differentially expressed weeks 16 relative to non-pregnancy (“open” cows). Weeks 8, 12 and 16 of pregnancy commonly showed a distinct increase in circulating levels of miR-221 and miR-320a. Through genome-wide analyses we have successfully profiled plasma miRNA populations associated with pregnancy in cattle. Their application in the field of reproductive biology has opened up opportunities for research communities to look for pregnancy biomarker molecules in dairy cattle.
        4,000원
        128.
        2021.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In this study, using the plasma spray method, tensile and compression fatigue tests are performed in saline solution to examine the effect of Ti undercoat on corrosion fatigue behavior of alumina-coated specimens. The alumina-coated material using Ti in the undercoat shows better corrosion fatigue strength than the base material in the entire stress amplitude range. Fatigue cracking of UT specimens occurs in the recess formed by grit-blasting treatment and progresses toward the base metal. Subsequently, the undercoat is destroyed at a stage where the deformation of the undercoat cannot follow the crack opening displacement. The residual stress of the UT specimen has a tensile residual stress up to about 100 μm below the surface of the base material; however, when the depth exceeds 100 μm, the residual stress becomes a compressive residual stress. In addition, the inside of the spray coating film is compressive residual stress, which contributes to improving the fatigue strength characteristics. A hardened layer due to grit-blasting treatment is formed near the surface of the UT specimen, contributing to the improvement of the fatigue strength characteristics. Since the natural potential of Ti spray coating film is slightly higher than that of the base material, it exhibits excellent corrosion resistance; however, when physiological saline intrudes, a galvanic battery is formed and the base material corrodes preferentially.
        4,000원
        129.
        2020.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In the present study, we examined the effect of straw size on spermatozoa motility, viability, acrosome integrity, mitochondrial membrane potential, and plasma membrane integrity after freezing-thawing. Hanwoo semen was collected from three bulls and diluted with an animal protein-free extender, divided into two groups, namely, 10 million spermatozoa in 0.25 mL and 20 million spermatozoa in 0.5 mL straw, and cryopreserved. In Experiment 1, the motility and motility parameters of the frozenthawed spermatozoa were evaluated. After freezing-thawing, the spermatozoa motility parameters fast progressive, straight line velocity, and average path velocity were compared between the 0.25 mL straw and 0.5 mL straw groups. They were 35.2 ± 1.0 and 32.3 ± 0.7%, 34.6 ± 0.7 and 31.8 ± 0.5 μm/s, 51.4 ± 1.3 and 47.1 ± 1.1 μm/s, 0.25 mL straw and 0.5 mL straw groups, respectively. In Experiment 2, the viability, acrosome membrane integrity, and mitochondrial membrane potential of the frozen-thawed spermatozoa were assessed. After freezing-thawing, the percentages of spermatozoa with live, intact acrosomes and high mitochondrial membrane potential were compared between the in 0.25 mL straw and 0.5 mL straw groups. They were 48.0 ± 2.6% and 35.6 ± 2.8% between the 0.25 mL straw and 0.5 mL straw groups. In Experiment 3, the plasma membrane integrity of frozen-thawed spermatozoa was compared. After freezingthawing, the plasma membrane integrity was higher for the in 0.25 mL straw group than the 0.5 mL straw group. They were 62.0 ± 2.2 and 54.1 ± 1.3% between the 0.25 mL straw and 0.5 mL straw groups. In conclusion, our results suggest that freezing semen in 0.25 mL straw improves the relative motility, viability, and acrosomal, mitochondrial membrane potential, and plasma membrane integrity of Hanwoo bull spermatozoa.
        4,000원
        130.
        2020.12 구독 인증기관 무료, 개인회원 유료
        순환여과양식시스템(RAS)은 사육수를 여과하여 재사용하며 고밀도로 사육하는 양식 방법으로 수질관리 및 소독이 매우 중요하다. 병원체로 인한 질병 발생을 예방하고 수질 개선에 도움을 주기 위하여 최근 코로나 방전 플라즈마 처리수(plasma water, PW)를 이용한 사육수 소독법이 제안되었다. 본 연구에서는 플라즈마 발생장치를 설치한 순환여과시스템(처리구, PW system) 과 설치하지 않은 순환여과시스템(대조구, No PW system)에서 40일 동안 틸라피아를 사육하 면서 수질 변화 및 어체의 성장을 조사하였다. 이를 위해 10일 마다 물을 채수하여 UV 투과율 과 일반 세균 수 변화를 측정하였고 틸라피아의 성장지표, 생존율 및 조직학적인 차이를 분 석하였다. UV 투과율 실험 결과 처리구와 대조구는 실험 시작 시에(0일) 각각 74.1%, 74.8%를 나타냈으며, 40일째에 처리구는 91.8%로 증가한 반면 대조구는 65.2%로 감소하여 수중 유기 물 감소 효과를 확인하였다. 일반 세균 수는 40일에 이르러 처리구(101.69 CFU/ml)에서 대조구 (103.25 CFU/ml) 보다 유의하게 감소하였다(p<0.05). 틸라피아 성장차이 조사 결과 처리구는 대조구에 비해 총 증중량이 유의하게 높았으며(p<0.05), 다른 성장지표도 처리구가 상대적으로 높았으나 통계적으로 유의한 차이는 아니었다(p>0.05). 또한 처리구는 100%의 생존율을 보였 으며, 조직학적으로 대조구와 차이가 나타나지 않았다. 따라서 플라즈마 처리수는 순환여과양 식시스템 내 어류의 성장과 건강에 해를 끼치지 않고 수질 개선에도 효과가 있을 것으로 기대 된다. 그러나 현장 적용 시에는 탈기수조의 설치 등 주의사항을 충분히 고려하여야 할 것이다.
        4,000원
        133.
        2020.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Dishwashing tools such as sponges, scourers, and dishcloths are known to harbor dense and diverse microbial communities, including pathogenic bacteria. In this study, the potential of corona discharge plasma jet (CDPJ) as a disinfectant was tested to improve the hygienic quality of dishwashing tools. For the simulation of microbial contamination, selective pathogenic bacteria (Escherichia coli O157:H7, Staphylococcus aureus, and Pseudomonas putida) were inoculated on selected dishwashing tools (dishcloth, sponge, and scourer) at concentrations of 6.55 to 8.77 log CFU/cm 2 . CDPJ generated at 20 kV voltage and 1.5A current was used for decontamination, whereas a sample-to-electrode distance of 25 mm was maintained during the treatment. Following CDPJ treatment for 5 min, the viable counts of E. coli O157:H7, S. aureus, and P. putida were reduced by 4.30-4.56, 3.71-4.78, and 3.50-3.83 log, respectively. The rates of inactivation were varied among the pathogens, decreasing in the order E. coli O157:H7 > S. aureus > P. putida. Among tested kinetic models, namely log-linear, log-linear with shoulder, and Weibull models, the log-linear with shoulder model was found to be the most suitable model to explain the CDPJ inactivation of the pathogens. In conclusion, CDPJ can be used as a potential sanitizing agent for dishwashing tools.
        4,000원
        134.
        2020.11 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        This study is aimed at preparing and evaluating the plasma resistance of YAS (Y2O3-Al2O3-SiO2) coating layer with crystalline YAG phase contents. For this purpose, YAS frits with controlled phase contents are prepared and melt-coated on sintered Al2O3 ceramics. Then, the results of phase analysis of crystalline YAS coating layer are compared to that of YAS frits, and discussed with regard to the plasma resistance of the YAS coating layer. The phase contents of the YAS frit change in a manner different from that of the prepared YAS coating layer, presumably owing to the composition change of YAS frit during the melt-coating process. The plasma resistance of the YAS coating layer is shown to increase with the YAG phase contents in the coating layer. Comparing the weight loss of YAS coating layer with those of commercial Y2O3, Al2O3, and quartz ceramics, the plasma resistance of the prepared YAS coating layer is 8 times higher than that of quartz and 3 times higher than that of Al2O3; this layer shows 70 % of the resistance of Y2O3.
        4,000원
        136.
        2020.11 구독 인증기관·개인회원 무료
        본 연구에서는 malic acid가 혼입된 유청 분리 단백질(whey protein isolate; WPI) 소재 항균 코팅(MA-WPI)과 포장 후(in-package) 유전체 장벽 방전 대기압 콜드 플라즈마(atmospheric dielectric barrier discharge cold plasma; ADCP)의 병합 처리가 닭가슴살 가공육에 오염된 Salmonella와 Listeria monocytogenes 저해 효과를 확인하였다. 3% (w/w, total coating solution) malic acid가 혼입되지 않거나 혼입된 WPI 코팅 용액으로 코팅된 닭가슴살 가공육(2 ´ 2 cm; 원통형) 을 상업적으로 사용되는 polyethylene terephthalate 용기(14 ´ 10 ´ 3 cm)에 15개씩 담아 ADCP 처리하였다. ADCP 처 리 전압(21, 24, 그리고 27 kV)과 처리 시간(1, 3, 그리고 5분)을 변수로 하여 닭가슴살 가공육에 접종된 Salmonella 저 해에 대한 최적 처리 조건(24 kV, 3분)을 결정하였고, 항균 코팅과 병합 처리 시 ADCP 처리 조건으로 사용되었다. 단 독 CP 처리, 단독 MA-WPI 코팅, 그리고 MA-WPI + CP 병합 처리 시 Salmonella는 각각 1.3 ± 0.1, 1.1 ± 0.2, 그리고 1.8 ± 0.1 log CFU/g만큼 저해되었고, L. monocytogenes는 0.9 ± 0.1, 0.5 ± 0.1, 그리고 1.3 ± 0.1 log CFU/g만큼 저해되 어 MA-WPI + CP 병합 처리가 각각의 단독 처리보다 Salmonella와 L. monocytogenes 저해 효과를 증가시킴을 알 수 있었다(p<0.05). 본 연구의 결과는 in-package ADCP 처리와 MA-WPI 항균 코팅의 병합 처리가 미생물을 효과적으로 저해시키는 포장 후 비가열 처리 기술로서의 가능성이 있음을 보여주었다.
        137.
        2020.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to examine the effects of Atractylodes lancea (A.l.) in a dose-dependent manner on lipid levels and plasma glucose in diabetic rats induced with streptozotocin (STZ). The Sprague-Dawley rats were randomly classified into five groups: normal, STZ-control and three experimental groups [A.l.-1, diabetic treated with ethanolic extract of A.l. (1 g/kg b.w.), A.l.-2, diabetic administered with ethanolic extract of A.l. (2 g/kg b.w.), and A.l.-3, diabetic administered with ethanolic extract of A.l. (3 g/kg b.w.)]. The normal and STZ-control group were fed an AIN-93 diet and the three experimental groups were administered with A.l. extract at doses of 1, 2, and 3 g/kg b.w./day, respectively, for 14 days. The plasma glucose levels in all the experimental groups were significantly lower than the STZ-control group after 14 days of treatment. The total cholesterol of the A.l.-3 and triglyceride levels, atherogenic index (AI) of all three experimental groups were significantly lower than the STZ-control group. The ALT and AST activities at A.l.-2, A.l.-3 were significantly lower than the STZ-control group. This result that demonstrate the administration of Atractylodes lancea can reduce hyperglycemia and hyperlipidemia risk in diabetic rats.
        4,000원
        138.
        2020.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 플라즈마 발생장치를 수경재배 시스템과 결 합하여 재배 기간 동안 처리 시 상추의 생육 및 기능성 물질 함량 변화를 살펴보기 위해 실시하였다. 3주 동안 육묘하여 균일 한 크기의 상추 묘를 semi-DFT에 정식하였으며, 플라즈마 공정 장치를 결합하여 4주 동안 8시간 주기로 1시간씩 수중에서 간헐적으로 작동시켰다. 양액(대조구), 플라즈마 활성수 (4.2kV, 5.7kV)를 사용하여 온실에서 재배하였으며 이후 수확하여 생육조사 및 기능성 물질 분석을 실시하였다. 플라즈마 활성수 처리 기간 동안 발생되는 활성산소종 중에서 O3로 인하여 플라즈마 발생 장치에 근접한 개체일수록 갈색 반점 및 괴사현상이 나타났으며, 생육조사를 실시한 결과 유의적 차이가 나타나지 않았다. 기능성 물질 분석 결과 상추 지상부의 rutin과 총 페놀 함량은 플라즈마수보다 높았지만, epicatechin 의 경우 플라즈마수 처리에서 함량이 더 많았다. 근권부에서 측정된 이차대사산물인 rutin, epicatechin, quercetin 및 총 페놀 함량은 대조구보다 플라즈마수 처리구에서 유의하게 높았다. 이러한 결과는 플라즈마수 처리 시간동안 수중에 오존과 같은 활성산소종으로 인해 지상부 생육이 잘 이루어지지 못했으나, 근권 영역에서는 이차대사산물이 크게 증가하였다. 향후 간헐적인 플라즈마 활성수 생성에 따른 생리 장해를 극복 하고 뿌리채소의 수경재배 시스템에 적용하여 이차대사산물 을 증가시키기 위한 본 기술의 도입이 필요하다.
        4,000원
        139.
        2020.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The enamel powders used traditionally in Korea are produced by a ball-milling process. Because of their irregular shapes, enamel powders exhibit poor flowability. Therefore, polygonal enamel powders are only used for handmade cloisonné crafts. In order to industrialize or automate the process of cloisonné crafts, it is essential to control the size and shape of the powder. In this study, the flowability of the enamel powders was improved using the spheroidization process, which employs the RF plasma treatment. In addition, a simple grid structure and logo were successfully produced using the additive manufacturing process (powder bed fusion), which utilizes spherical enamel powders. The additive manufacturing technology of spherical enamel powders is expected to be widely used in the field of cloisonné crafting in the future.
        4,000원