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        검색결과 137

        25.
        2019.06 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        Acute myocardial infarction (AMI) is considered the major cause of mortality in the world. Tremendous animal studies are performed to develop novel therapeutics, and this study aimed to induce porcine myocardial infarction model by using polyethylene terephthalate (PET). Coronary guidewire was placed in left anterior descending artery (LAD). The balloon angioplasty catheter was inserted at the back of the PET. The balloon catheter was carefully pushed forward, until the balloon marker was located in mid-LAD. Coronary angiography was performed pre- and post-occlusion at 28 days by C-arm. Histologic analysis of heart tissue was performed 28 days after inducing AMI. Thirty three pigs were anesthetized and underwent percutaneous coronary catheterization. All pigs were successfully embolized in mid-LAD by PET. Fifteen pigs died due to ventricular fibrillation during post-anesthetic recovery time, and overall experiment mortality was 45.5%. In 2,3,5- triphenyl tetrazolium chloride staining, gross finding of the ischemic heart lesion showed firm and white area of infarction associated with the apex and left ventricular posterior wall. Infarct on H&E-stained sections demonstrated a region without myocytes and rich with cardiomyocyte with atypical nuclei. Successful induction of AMI by using PET may provide the pathophysiological information of ischemic heart disease and improvement of therapy development for AMI.
        4,000원
        26.
        2019.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We report a facile and versatile strategy to prepare multi-dimensional nanocarbons hybridized with mesoporous SiO2. Carbon nanoplatelets (CNPs, two-dimensional structure of nanocarbons) were combined with carbon nanotubes (CNTs, onedimensional nanocarbons) to form multi-dimensional carbons (2D–1D, CNP–CNTs). The CNP–CNTs were synthesized by directly growing CNTs on CNPs. A simple solution-based process using TEOS (tetraethyl orthosilicate) resulted in coating or hybridizing CNP–CNTs with mesoporous silica to produce CNP–CNTs@SiO2. The nanocarbons’ surface area significantly increased as the amount of TEOS increased. Electrochemical characterizations of CNP–CNTs@SiO2 as supercapactior electrodes including cyclic voltammetry and galvanostatic charge–discharge in 3 M KOH (aq) reveal excellent-specific capacitance of 23.84 mF cm−2 at 20 mV s−1, stable charge–discharge operation, and low internal resistance. Our work demonstrates mesoporous SiO2 on nanocarbons have great potential in electrochemical energy storage.
        4,000원
        27.
        2019.04 구독 인증기관·개인회원 무료
        거미는 산림 및 농작물 해충의 천적으로 알려져 있으며, 겨울철 벼 재배지에서 볏짚이나 논둑 등에 월동한다. 이 연구는 월동시기부터 모내기 전까지 유기 벼 재배지에 서식하는 거미상을 알아보기 위해 수행하였다. 거미의 발생을 조사하기 위해 함정트랩을 이용하였고, 농업과학원 유기재배포장에서 2018년 1월 중순부터 5월 중순까지 2주 간격으로 총 8회에 걸쳐 거미를 채집하였다. 조사가 이루어진 논은 거미가 월동 서식처로 이용할 수 있도록 볏짚을 걷어내지 않은 상태로 유지하였다. 조사 결과 6과 15종 359개체의 거미가 채집되었다. 그 중에서 애접시거미가 119개체(33%)로 가장 많았고, 들늑대거미(23%), 턱거미(17%), 각시긴손접시거미(8%) 순으로 나타났다. 또한 4월 중순(7회)에 가장 많은 개체가 채집되었고, 채집이 이루어질수록 거미의 개체수가 증가하는 경향을 보였다.
        30.
        2018.10 구독 인증기관·개인회원 무료
        누에는 약제, 면직, 식용, 동물 사료 등에 활용도가 높아 동아시아에서 오랫동안 사육되어 왔다. 뽕잎을 먹고 자란 누에가 사료를 먹고 자란 누에보다 생장주기가 일정하고 더 건강하게 생장한다는 것은 잘 알려진 사실이다. 또한 최근의 연구에 따르면 동물 장내 미생물이 동물의 면역과 생장에 큰 역할을 한다고 알려졌다. 이러한 사실로부터 뽕잎에 존재하는 미지의 미생물이 누에 생장과 면역에 관여할 수 있다는 가설을 세우고 이를 확인하기 위한 연구를 수행하였다. 뽕잎 내생균을 분리하기 위해 뽕잎을 5mm 크기로 잘라 표면살균 후, 배지에 치상하여 자라나오는 세균을 분리하여 동정하였다. 흥미로운 점은 100개 이상의 뽕잎 절편으로부터 동일한 세균이 검출되었으며 계통학적 분석을 통해 동정한 결과, Pseudomonas syringae pv. syringae(Pss)로 확인되었다. 또한, 뽕잎을 섭식한 누에의 장 속과 분변에서 이 균의 존재를 확인하였다. 누에에 병을 일으키는 곤충병원성 곰팡이에 대한 Pss의 항진균 효과를 확인하기 위해 곤충병원성 곰팡이인 Beauveria bassiana, Cordyceps militaris와 식물병원성 곰팡이 Botrytis cinerea, Fusarium graminearum을 대상으로 대치배양을 통해 균사 생장 억제 정도를 확인하였다. 그 결과, 식물병원성 곰팡이의 생장 억제효과는 관찰되지 않았으나 곤충병원성 곰팡이의 생장이 50% 이상 감소되었다. 특히, 다량의 포자를 생성하여 곤충에 치명적인 병을 야기하는 B. bassiana의 균사 생장이 C. militaris에 비해 더 크게 감소하였을 뿐 아니라 Pss의 배양 추출물을 처리하였을 때 B. bassiana의 포자 발아가 지연되었다. 앞으로 누에 장 속에 안착한 Pss가 곤충병원성 곰팡이에 대한 면역력과 누에 생장에 미치는 영향을 확인해 볼 계획이며 이를 통해 건강하고 안정적인 누에 사육에 활용될 수 있는 미생물 제제를 만들고자 한다.
        32.
        2018.05 구독 인증기관·개인회원 무료
        The Semi-Rigid Pavement (SRP) mixture is composed of Gap Graded Asphalt (GGA) mixture (air void = 20~28%) and cement paste. By inserting cement paste into voids in GGA mixture, SRP can provide not only flexibility but also rigidity characteristics on pavement performance. SRP can mitigate pavement surface temperature increase during summer session, provide better smoothness and mitigate rutting distress due to heavy weight vehicles, successfully. In Japan, SRP is widely applied in cross section area, heavy vehicle parking lot and highway ticketing booth in highway network system. In South Korea, SRP was introduced and applied since 2005. However, still more researches and studies are needed to understand material characteristics and improve performance of SRP. Moreover, the current SRP system in South Korea merely follows and adapts the aggregate gradation information from Japan which needs to be amended and customized into original material (i.e. aggregate, binder and cement) situation of South Korea. In this paper, SRP system based on Stone Mastic Asphalt (SMA) mixture design originated from Korea Expressway Corporation (KEC) and enhanced cement paste with addition of fly-ash and slags was developed. In addition, an optimized proportion between asphalt mixture air voids and cement paste amount with consideration of economic benefit was introduced. Based on field evaluation process it can be said that the newly developed SRP system can successfully adapted not only in static site on highway: parking lots or ticketing booth, but also in dynamic site on highway: driving and wheel path.
        33.
        2018.05 구독 인증기관·개인회원 무료
        In case of performing asphalt pavement overlay on existing concrete pavement layer, applying asphalt emulsion tack-coating or spreading prime-coating is considered to improve adhesion between asphalt and concrete layer. After coating work is done a curing process is considered not only for promoting evaporation process in coated (and/or spread) asphalt emulsion, but also for generating a membrane which can act as a bonding agent. Finally, asphalt overlay construction is performed when this curing process is completely done. However, during asphalt overlay construction process remarkable amount of spread tack-coating layer is lost due to asphalt material transfer vehicles (e.g. trucks, approximately 40~50% of total spread tack coating material is lost). In this paper, a new pavement equipment contains simultaneous asphalt emulsion spreading ability and corresponding construction techniques are introduced. Through applying this equipment, non-stop two step sequent working process: spreading asphalt emulsion on to existing concrete pavement layer then paving asphalt material for overlay construction, is available. During pavement working process temperature of asphalt material was kept with ranged between 130ºC and 170ºC. After performing field performance evaluation, it was found that crucial improvement in pavement layer adhesion, crack and rutting resistant ability were observed compared to the conventional paving method.
        34.
        2017.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was performed to investigate how changing the period of light and dark influences the vegetative growth and the photosynthesis of Doritaenopsis Queen Beer ‘Mantefon’. Clones of Dtps. Queen Beer ‘Mantefon’ at 4-month-old stage were grown in a closed-plant factory system with four different light/dark cycles; 06/06 h, 08/08 h, 10/10 h, and 12/12 h. Temperature and relative humidity were set at 28oC and 80%, respectively, with a photosynthetic photon flux density of 160 ± 10 μmol·m-2·s-1. Repetitive measurements showed that the leaf length and the leaf width were the longest under 12/12 h closely followed by 10/10 h. The fresh weight and the dry weight of leaves and roots were the heaviest at 10/10 h treated samples. Different CO2 uptake patterns were observed from different light/dark cycles. Under 10/10 h and 12/12 h treatments, the CO2 uptake started at early dark period. When the light/dark cycles were shortened to 06/06 h and 08/08 h, the CO2 uptake started at the middle of dark period. Total CO2 uptake amounts were the highest under 12/12 h treatment followed by 10/10 h, 06/06 h, and 08/08 h treatments. Quantitative measurements showed that the vegetative growths under 10/10 h treatment were comparable with that of 12/12 h treatment. These studies indicated that manipulating light/dark can modify the photosynthesis patterns and vegetative growth of Dtps. Queen Beer ‘Mantefon’, resulting in the reduction of the production period.
        4,000원
        39.
        2017.05 구독 인증기관·개인회원 무료
        Somatic cell nuclear transfer (SCNT) is the technique which generates embryos by transferring diploid nucleus into an enucleated oocyte, it has produced specific animals successfully in a variety of species. However, the developmental capacity of SCNT embryos is still relatively lower than that of embryos produced in vivo. Oocyte is a kind of lipid rich cells, its quality limits the efficiency of embryo production. L-carnitine is a co-enzyme facilitating the transportation of long chain fatty acids across the inner mitochondria membrane where fatty acids are used for generating adenosine triphosphate (ATP) via beta-oxidation. It also has antioxidant actions which may protect mitochondrial membranes and DNA against damage induced by reactive oxygen species (ROS). Whether L-carnitine is functional in bovine SCNT embryos are unknown. Therefore, the objective of this study was to examine the effects of L-carnitine on oocyte maturation and developmental competence of subsequent SCNT embryos. L-carnitine was supplemented during IVM, then intracellular ROS and GSH levels, mitochondrial activity, gene expression of COCs were analyzed at the end of IVM. SCNT embryos were produced subsequently, apoptosis detection and gene expression evaluation were performed in blastocysts. In the results, treatments with 1.5 mM and 3 mM L-carnitine significantly improved maturation rates (P<0.05). Treatments with 3 mM L-carnitine effectively induced improvement in nuclear maturation, intracellular GSH levels and mitochondrial activity, as well as a reduction in intracellular ROS levels (P<0.05). mRNA levels of CPT1A, ACAA1, ACAA2, AREG, EREG, SOD1, GPX4, GLUT1 and CDC2 transcripts were effectively up-regulated by 3 mM L-carnitine treatments (P < 0.05). Similarly, 3mM L-carnitine induced an increase in blastocyst developmental rates and an improvement in blastocyst quality (P<0.05). Our study indicates that L-carnitine treatment during IVM improves oocyte nuclear maturation and subsequent SCNT embryo development.
        40.
        2017.05 구독 인증기관·개인회원 무료
        The mesenchymal stem cells (MSC) has been investigated as a source of stem cell therapy to replace and treat damaged cells. Human endometrial epithelial and stromal cells was isolated from hysterectomy tissue and the direct evidence of stem/progenitor cells in the human endometrium was identified. Endometrium derived stem cells (EnMSCs) are known to have a high proliferative ability, genetic stability, lack of tumorigenicity and low immnunogenicity during long-term cultivation. Here, we aimed to identify MSC in canine endometrium and characterize its potential to differentiate into decidua cells. EnMSCs were isolated from thrown-away spayed uterus of adult canine depending on their estrus cycle, and identified by flow cytometry, immunocytochemistry and flow cytometry with MSC specific markers. We then characterized the ability of EnMSCs by the doubling-time analysis, colony-forming units and MSC differentiation assays. Isolated EnMSCs expressed stem cell specific genes (Sox2, Oct4, Nanog, MCAM, Endoglin, Susd2 and IGTB) and MSC surface markers (CD90, CD44 and CD117). EnMSCs are also differentiated into adipogenic, osteogenic and chondrogenic cells morphologically under modified conditions with the expression of lineage specific genetic markers. EnMSCs showed higher proliferation ability than canine amniotic fluid derived MSCs which were used as a positive control. EnMSCs were cultured at low density (10, 20, cells/cm2) and initiated to form small colonies of loosely-arranged cells and gradually formed large colonies of densely-packed cells which underwent self-renewal with high proliferative potential which is similar to the clonogenicity feature of human endometrium-derived stem cells. EnMSCs were then induced to differentiate into decidua cells with 0.5 mM dbcAMP. After 14 days, EnMSCs changed their morphology into the elongated and rounded shape. The induced decidual cells expressed PRL and IGFBP1 which are typically expressed in decidua cells. In conclusion, we successfully isolated and characterized MSC in the canine endometrium which differentiated into decidua cells. These results showed that endometrium may be a promising source of stem cells, and furthermore raise the possibility of canine EnMSCs as a novel hypothetical decidualisation model of infertility associated with decidualisation insufficiency and implantation failure.
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