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        검색결과 591

        1.
        2025.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 딥러닝 영상 재구성 기법을 적용한 8개의 뇌질환군의 감마나이프 수술 계획용 자기공명영상(magnetic resonance imaging, MRI)의 유용성을 알아보고자 하였다. 연구 방법은 전이성 뇌종양, 뇌동정맥 기형, 수막종, 뇌하수체선종, 삼차신경통, 청신경초종, 맥락얼기 유두종, 해면상 혈관종, 총 8개의 질병을 진단받은 사람들의 T2 강조 영상(T2 weighted imaging, T2WI), 조영증강 T1 강조영상(contrast enhancement T1 weighted imaging, CE-T1WI)의 방법으로 검사한 MRI 영상을 SwiftMR을 이용하여 딥러닝 영상 재구성 기법인 디노이징(denoising)과 초해상도(super resolution)가 적용된 영상을 획득하였다. 이에 대한 성능 평가는 최대 신호대잡음비(peak signal to noise ratio, PSNR), 구조적 유사도(structural similarity index measure, SSIM), 감마나이프 방사선수술(gamma knife radiosurgery, GKRS)의 좌표계로 평가하였다. 그 결과, 원본영상을 기반으로 영상 품질이 개선된 영상의 PSNR과 SSIM은 높은 수치를 나타냄으로써 MRI 영상의 재구성이 문제없이 이루어졌고, GKRS의 수술 좌표계 또한 변화를 보이지 않았다. 결론적으로 딥러닝 영상 재구성 기법은 영상 품질 향상과 영상 보존에서 뛰어난 성능을 보임과 동시에 좌표계도 변화를 보이지 않아서, 딥러닝 영상 재구성 기법은 감마나이프 수술 계획에 유용하게 사용할 수 있는 기법임을 확인하였다.
        4,000원
        2.
        2025.01 KCI 등재 구독 인증기관 무료, 개인회원 유료
        국내 수박(Citrullus lanatus) 품종의 발아율에 대한 Solid Matrix Priming(SMP)의 영향을 평가하였다. Micro cel-E가 SMP 처리에 가장 이상적인 matrix로 밝혀졌으며, 종자:matix:물의 비율은 10:5:10(w/w/w)로, 25°C 에서 3일 동안 처리했을 때 유근의 돌출없이 발아속도가 촉진되었다. SMP 처리 과정 동안 초기 4시간 동안의 수분 흡수율은 급격하게 증가했으며, 이후 72시간 동안은 더 느린 속도로 흡수되었고, 처리 마지막 시간까지 수분 흡수 율은 41%이었다. 발아 온도와 상관없이, SMP 처리된 종자는 발아 시간이 단축되면서 발아율이 향상되었다. 특히, 최적 발아 온도보다 낮은 온도에서 발아율이 높았다. 품종별 차이는 있었으나, 특히 ‘해찬꿀’과 ‘리코스위트’ 품종 에서 발아율이 유의미하게 증가하였다. 또한 일부 품종에서 SMP 처리 종자의 유묘출현율과 초장, 생체중이 무처 리에 비하여 증가한 값을 보였으며, SMP 처리로 종자의 발아속도 및 유묘활력을 증진시켜 우량 묘 확보가 가능한 것으로 판단되었다.
        4,000원
        3.
        2024.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Moringa oleifera, a versatile plant, has been traditionally used to treat various ailments and is gaining scientific attention due to its potential as a medicine. Native to the Indian subcontinent, it is widely grown in tropical and subtropical regions, thriving in Asia, Africa, and South America, especially in arid climates. This study explores the antioxidant potential of Moringa oleifera leaf extract (MOLE), employing a comprehensive screening approach with various solvents to identify the most effective extraction method. Initial experiments assessed antioxidant efficacy and yield using distilled water (D.W.), 95% ethanol, and 95% methanol. Among these, 95% ethanol extract demonstrated superior antioxidant activity, confirmed through assays such as 2,2-diphenyl-1-14 picrylhydrazyl (DPPH) radical scavenging assay, total polyphenol content analysis, and reducing power assay. In addition, with the 95% ethanol MOLE, a higher extraction efficiency was yielded compared to other solvents, making it the most effective for large-scale preparation. HPLC analysis revealed the presence of key bioactive compounds, including ellagic acid, rutin, Q-3-O, quercetin, and kaempferol. Results revealed that MOLE, prepared using 95% ethanol, exhibited remarkable antioxidant properties, attributed to its rich polyphenolic content. This research underscores the therapeutic potential of MOLE as a natural antioxidant source and highlights the importance of solvent optimization in phytochemical extractions.
        4,000원
        4.
        2024.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Clove (Syzygium aromaticum) is a highly valued medicinal plant native to Aisa. Widely used as a spice, renowned for its medicinal properties, particularly in Ayurveda and traditional Chinese medicine. In this study, clove bud extract (CBE) was prepared at different ethanol concentrations of 50%, 80%, and 90%, respectively. The antioxidant activity of the CBE was evaluated through DPPH, polyphenol, and reducing power assays, revealing its strong antioxidant potential, with 90% ethanol being the most effective extract. HPLC analysis identified eugenol (8.7 mg/g) as the major active compound, known to possess anti-inflammatory and antioxidant properties. Given the role of oxidative stress and inflammation in atopic dermatitis (AD), the therapeutic potential of CBE was explored using a 1-chloro-2, 4-dinitrobenzene (DNCB)-induced AD mouse model. Five-week-old BALB/c mice were induced with AD by topical application of DNCB. CBE was administered topically to the affected skin (back and ear) areas for 4 weeks. The treatment of CBE significantly reduced the severity of clinical dermatitis, decreased epidermal thickness, and lowered mast cell and eosinophil infiltration in skin tissue, as observed through hematoxylin eosin staining and toluidine blue staining. The results demonstrated CBE as a promising therapeutic agent for managing AD through its regulation of skin inflammation and oxidative stress, making it a potential candidate for future treatments of inflammatory skin disorders.
        4,000원
        5.
        2024.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Following the previous study, which investigated the pharmacological properties of the Technekitty injection (Tc-99m), the toxicity of a single intravenous administration of the Technekitty injection (Tc-99m) and the side effects that may occur at the diagnostic dose were confirmed. The Technekitty injection (Tc-99m) was administered intravenously once at a dose of 0, 0.67, 2.0, and 6.0 mCi/kg to 5 male and female rats per group. Mortality, general symptom observation, and weight measurement were performed for 2 weeks, followed by observation of autopsy findings. There were no deaths, and no statistically significant weight change was observed. No abnormal systemic signs related to the Technekitty injection (Tc-99m) were observed. These results confirmed that Technekitty injection (Tc-99m) can be safely administered intravenously at doses up to 6.0 mCi/kg. Additionally, technetium-99m at an average dose of 2 mCi (74 MBq) has been verified as a diagnostic dose without adverse effects, allowing the Technekitty injection (Tc-99m) to be used safely without side effects at this dosage. This study demonstrates that the Technekitty injection (Tc-99m) has a wide safety margin, supporting its potential for clinical application. Moreover, these findings align with the nonclinical safety standards for radiopharmaceuticals, reinforcing its utility in veterinary medicine. The Technekitty injection (Tc-99m) is expected to be applicable for clinical diagnosis as a veterinary drug in Korea.
        4,000원
        6.
        2024.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Thyroid scanning using technetium-99m (99mTc) is the gold standard for diagnosing feline hyperthyroidism. In cats with an overactive thyroid, a thyroid scan is the most appropriate imaging technique to detect and localize any hyperfunctional adenomatous thyroid tissue. In this study, the pharmacological properties of the Technekitty injection (Tc-99m), developed as a diagnostic agent for feline hyperthyroidism using 99mTc as an active ingredient, were tested in FRTL-5 thyroid follicular cell line and ICR mice. The percentage of cell uptake of the Tc-99m in FRTL-5 thyroid cells was 0.182 ± 0.018%, which was about 6 times higher compared to Clone 9 hepatocytes. This uptake decreased by 38.2% due to competitive inhibition by iodine (sodium iodide). In tissue distribution tests by using ICR mice, the highest distribution was observed in the liver, kidneys, spleen, lungs, and femur at 0.083 hours after administration, and this distribution decreased as the compound was excreted through the kidneys, the primary excretory organ. Maximum distribution was confirmed at 1 hour in the small intestine, 6 hours in the large intestine, and 2 hours in the thyroid gland. Additionally, the total amount excreted through urine and feces over 48 hours (2 days) was 78.80% of the injected dose, with 37.70% (47.84% of the total excretion) excreted through urine and 41.10% (52.16% of the total excretion) through feces. In conclusion, the Tc-99m has the same mechanism of action, potency, absorption, distribution, metabolism, and excretion characteristics as 99mTc used for feline hyperthyroidism in the United States, Europe, and other countries, because the Technekitty injection (Tc-99m) contains 99mTc as its sole active ingredient. Based on these results, the Technekitty injection (Tc-99m) is expected to be safely used in the clinical diagnosis of feline hyperthyroidism.
        4,800원
        7.
        2024.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Despite the widespread recognition of the prominent contribution of key language subskills, such as grammar and vocabulary knowledge, to reading comprehension, a research consensus on their relative significance has not been reached. Moreover, the extent of the contribution vocabulary depth makes to reading comprehension has received little research attention. The present study assessed the relative potential contribution of vocabulary depth and grammar knowledge to advanced Korean EFL college students’ reading comprehension abilities, while controlling for their language proficiency and vocabulary breadth, through hierarchical regression analyses. 56 advanced EFL Korean college students were tested on reading comprehension abilities and a range of reading-related subskills including vocabulary breadth, vocabulary depth, grammar, and listening comprehension in English. The findings revealed the unique contribution of vocabulary depth to reading comprehension abilities beyond the effects of both vocabulary breadth and grammar knowledge when English proficiency was controlled for. The findings further underscore the need for balanced approaches in developing L2 learners’ language skills to enhance their reading comprehension abilities.
        6,100원
        11.
        2024.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Hanwoo cattle farmers aim to improve calf production and reproductive efficiency. Recovery of the reproductive tract postpartum is a critical factor influencing the postpartum period and conception of breeding cows. This study aimed to precisely analyze the recovery process of the reproductive tract in primiparous Hanwoo postpartum and to establish recovery criteria. Methods: Ten primiparous Hanwoo cows were used in this study. After parturition, estrus was examined daily using visual observations and estrus detection patches. Ovarian recovery, cervical diameter, and uterine horn diameter were examined using ultrasonography four times per week. Results: The analysis revealed that the first estrus occurred at 19.1 ± 6.5 days postpartum, the first ovulation at 27.1 ± 4.5 days, and the first normal estrus cycle at 39.2 ± 6.4 days. The ovulation rate during the first estrus was 40%. A normal estrus cycle occurred in 11.1% of patients at the first ovulation. The cervix diameter recovered to 42.0 ± 3.5 mm and the uterine horn diameter to 34.4 ± 7.1 mm by 24 days postpartum, with the difference in uterine horn diameter recovering to 2.6 ± 1.2 mm by 31 days postpartum. Conclusions: This study can aid in determining the optimal breeding time for postpartum primiparous Hanwoo cow and provide foundational data for Hanwoo breeding studies.
        4,200원
        12.
        2024.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        국제해사기구는 국제해운의 온실가스 배출을 줄이기 위한 전략을 채택하였으며, 선박 기인 온실가스 배출을 줄이기 위해 보다 강화된 목표를 설정하고 있다. 액체수소를 기화시켜 연료로 사용하는 고분자 전해질 연료전지는 이러한 규제를 준수하기 위한 유망한 기 술 중 하나로 평가받고 있다. 일반적으로 선박시스템 설계는 선급의 규정에 따라야 하지만 환경규제가 강화됨에 따라 새로운 연료와 시 스템의 도입이 가속화되고 있으며, 이로 인해 규정개발이 기술의 도입을 따라가지 못하는 경우도 발생하고 있다. 이러한 격차를 해소하기 위해, 본 연구에서는 수소 연료가스공급 시스템을 대상으로 위험요소 및 운전분석 기법(HAZOP)과 보호계층분석 기법(LOPA)을 결합하여 신기술의 안전성을 검증하는 방법을 제시하였다. 먼저 HAZOP을 통해 위험 시나리오를 식별하고, LOPA를 통해 정성적인 HAZOP 결과를 정량적으로 보완하였다. 초기사건의 빈도와 독립보호계층(IPL)들의 작동 요구시 고장 확률(PFD)을 계산하였다. 기존 IPL의 적절성을 결정 하기 위해, 예상되는 완화 정도를 가정한 허용기준과 비교하였으며, 필요한 경우, 추가 IPL을 권장하였다. 본 연구를 통해서 HAZOP-LOPA 기법이 조선해양 분야에서 신기술의 안전성을 평가할 수 있는 잠재력을 가지고 있음을 확인하였다.
        4,300원
        13.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Platelet-derived growth factor receptor alpha (PDGFRα) is essential for various biological processes, including fetal Leydig cell differentiation. The PDGFRαEGFP mouse model, which expresses an eGFP fusion gene under the native Pdgfrα promoter, serves as a valuable resource for exploring PDGFRα’s expression and function in vivo. This study investigates PDGFRα expression in adult testicular cells using PDGFRαEGFP mouse model. Methods: Genotyping PCR and gel electrophoresis were used to confirm the zygosity of PDGFRαEGFP mice. Histological examination and fluorescence imaging were used to identify PDGFRα expression within testicular tissue. Immunohistochemical analysis assessed the co-expression of PDGFRα with c-Kit, ANO-1, and TASK-1 in testicular cells. Results: Genotyping confirmed the heterozygous status of the mice, which is crucial for studies due to the embryonic lethal phenotype observed in homozygotes. Histological and fluorescence imaging revealed that PDGFRα+ cells were primarily located in the interstitial spaces of the testis, specifically within Leydig cells and peritubular myoid cells (PMCs). Immunohistochemical results showed PDGFRα co-localization with c-Kit and ANO-1 in Leydig cells and a complete co-localization with TASK-1 in both Leydig cells and PMCs. Conclusions: The findings demonstrate specific expression of PDGFRα in Leydig cells and PMCs in adult testicular tissue. The co-expression of PDGFRα with c-Kit, ANO-1, and TASK-1 suggests complex regulatory mechanisms, possibly influencing testicular function and broader physiological processes.
        4,000원
        16.
        2024.04 구독 인증기관·개인회원 무료
        Hindwings of many lycaenid butterflies have a unique tail-like wing structure referred to as a false head, which actually mimics the antennae. False heads increase butterfly survival by directing predatory attacks towards the false heads thereby enhancing the chance of escape. In this study, using discrete character evolution models of European and American butterflies, we examined the co-evolutionary patterns between false head structures and two associated traits: a highly contrasting color patch neighboring the false head, and hindwing rubbing behaviors. The former is considered a eye-mimicking structure that enhances the effectiveness of false head, and latter generates the movement of false heads which likely increases the success of false head deception. Our findings demonstrate that false heads are ancestral states for both European and American lycaenids. Both contrasting colors and hindwing rubbing behaviors follow correlated evolution models, suggesting that these traits co-evolved in lycanid butterflies. However, specific evolutionray patterns differed between the two continents.
        17.
        2024.04 구독 인증기관·개인회원 무료
        깡충거미과의 모습을 의태하여 시각적 포식자인 깡충거미로부터 자신을 보호하는 전략은 여러 나비목 곤충 에서 진화하였다. 하지만 나비목 곤충이 깡충거미 간의 의사소통 신호를 의태한다는 가설은 제안된 바 없다. 본 연구에서는 깡충거미과의 구애/영역성 행동을 의태하는 것으로 추정되는 붉은꼬마꼭지나방(Atkinsonia ignipicta)의 빗살 모양 더듬이와 추켜 올린 다리가 포식을 단념시키는 의태 신호로 작동하는지 실험적으로 검증 하였다. 깡충거미 의태라 추측되는 붉은꼬마꼭지나방의 형태적 및 행동적 특성들을 단계적으로 제외한 뒤 포식 자(흰눈썹깡충거미, Evarcha albaria)와의 조우 시 생존을 비교하였다. 연구 결과, 붉은꼬마꼭지나방은 비슷한 크기의 비-의태 나방에 비해 포식자의 공격을 덜 받았으며, 더듬이나 다리 중 하나라도 결여되었을 때 흰눈썹깡충 거미의 공격이 증가하였다. 이는 붉은꼬마꼭지나방의 더듬이와 다리 모두가 시각적 방어의 중요한 신호로 작동 한다는 것을 시사한다. 하지만 흰눈썹깡충거미가 붉은꼬마꼭지나방을 향해 구애/영역성 행동을 보이지 않았다 는 점에서 깡충거미의 낮은 공격 빈도가 같은 깡충거미 종류로 오인해서인지 다른 이유에서인지는 불투명하다. 그러나 사층깡충거미(Marpissa pulla)는 붉은꼬마꼭지나방을 상대로 영역성 행동을 잦은 빈도로 보였으며, 이는 붉은꼬마꼭지나방의 형태가 깡충거미 의태 효과를 가진다는 것을 보여준다.
        18.
        2024.04 구독 인증기관·개인회원 무료
        Distractive marking, as conceptualized by Abbott H. Thayer, refers to diminutive patterns of contrasting colors on an animal’s body. Thayer hypothesized that these patterns augment camouflage by diverting predatory focus from the outline of the prey, however, the evidence was insufficient. In this study, we verified the hypothesis that the presence of distractive markings confers a survival advantage under specific conditions. Specifically, the experiment aimed to ascertain whether the existence of lichens on trees hinders the visual detection of prey, given that lichens resemble distractive markings. The experimental design involved human subjects as predators and artificial moth images on a monitor as prey. The survival of moths with and without distractive markings was compared, also considering the influence of the presence of lichens in the background. As an analysis result, the survival likelihood of moths was statistically significantly hindered when the distractive marking was present. This result contradicts Thayer‘s hypothesis and implies the presence of a function distinct other than the enhancement of camouflage.
        19.
        2024.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        This study develops and validates an English communicative competence model for Korean high school students, in response to the need to redefine the relevant concepts and components of competence that are demanded by the rapidly evolving future society. Drawing on Celce-Murcia’s (2008) theoretical model on communicative competence, this research conceptualized a model that could assess high school students’ English communicative competence by examining relevant domestic and international studies as well as theoretical reflections. Expert opinions from a two-stage Delphi survey were compiled and incorporated to revise, supplement, and validate the English communicative competence among high school students reflecting Korea’s English education environment. Following this process, the conceptual model for English communicative competence was reorganized into five sub-competences (sociolinguistic, discourse, linguistic, interactional, and strategic competence) and 15 corresponding subfactors. The content validity ratio values for the conceptual definition and factor structure of this model were all above 0.64, thus affirming the validity of the conceptual definition and factor structure.
        5,800원
        20.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
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