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        검색결과 1,396

        2.
        2025.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, we analyzed the structural and mechanical properties of aluminum foams fabricated using aluminum powders of varying sizes and mixtures. The effects of sintering and pore structure at each size on the integrity and mechanical properties of the foams were investigated. Structural characteristics were examined using scanning electron microscopy and micro–computed tomography, while mechanical properties were evaluated through compression testing. The experimental results demonstrated that smaller powder sizes improved foam integrity, reduced porosity and pore size, and resulted in thinner cell walls. In combination, these effects increased compressive strength as the powder size decreased. The findings of this study contribute to the understanding and improvement of the mechanical properties of aluminum foams and highlight their potential for use in a wide range of applications.
        4,300원
        3.
        2025.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Italian ryegrass (Lolium multiflorum Lam., IRG) is a widely cultivated winter forage crop known for its high yield and nutritional value. This study evaluated the processing characteristics and feeding performance of IRG-based pellets in Hanwoo cattle (Bos taurus coreanae) and Korean native black goats (Capra hircus). IRG was harvested at the optimal growth stage and processed into two pellet formulations: IRG ≥80% (with up to 20% soybean meal) and 100% IRG. Feeding trials were conducted under ad libitum feeding conditions. Hanwoo cattle showed higher intake of 100% IRG pellets (7.9 kg/day/head) than IRG ≥80% pellets (7.5 kg/day/head, p<0.05), with similar average daily gain (0.9 ± 0.4 kg/day/head). Conversely, black goats exhibited significantly lower intake of IRG ≥80% pellets (54.6 g/day/head) compared to 100% IRG pellets (266 g/day/head), likely due to reduced palatability associated with soybean meal inclusion. These findings suggest that IRG pellets are suitable for Hanwoo cattle, while further optimization of pellet size and formulation is required to improve acceptance in goats. Future studies should assess long-term impacts on digestion, rumen fermentation, and metabolic responses.
        4,000원
        4.
        2025.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The commercial feed additive, native rumen microbes (RC), derived from a diverse microbial community isolated from the rumen of Hanwoo steers is being explored to enhance rumen fermentation and improve ruminant feed utilization. This study evaluated the impact of native rumen microbes supplementation on methane emissions, microbial diversity, and fermentation efficiency on in vitro assessment. Treatments were as follows: CON (basal diet, without RC); T1 (basal diet + 0.1% RC); T2 (basal diet + 0.2% RC). Rumen fermentation parameters, total gas, and methane production were assessed at 12, 24, and 48 h of incubations. The in vitro gas production was carried out using the Ankom RF Gas Production System. Supplementation of RC significantly reduced the total gas production at 12, 24, and 48 hours of incubation (p < 0.05). Volatile fatty acid concentrations were increased, while acetate and propionate were decreased (p < 0.05) at 48 h by the supplementation of RC. Notably, the 0.1% inclusion level of RC significantly reduced methane production by 28.30% and 21.21% at 12 and 24 hours. Furthermore, microbial diversity analysis revealed significant shifts (p < 0.05) in bacterial composition between the control and treatment groups, while supplementation also promoted the growth of bacterial populations, such as Succiniclasticum. These findings suggest that native rumen microbes supplementation, particularly at 0.1% inclusion level, can enhance rumen microbial composition while significantly reducing methane production in vitro.
        4,300원
        5.
        2025.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Heat stress during summer impairs reproductive performance in sows, causing summer infertility. Cytochrome P450 1A2 (CYP1A2) plays a crucial role in steroid hormone metabolism in the liver and has been shown to be upregulated under stress conditions. However, the effect of seasonal heat stress on CYP1A2 expression in sow ovaries remains poorly understood. Methods: Ovaries were collected from crossbred sows during different seasons in Korea. The control group (CON) was exposed to optimal temperatures for swine rearing (22.0-24.5℃) during spring, while the heat-stressed group (HS) experienced high temperatures (30.5-37.0℃) during summer. Temperature-humidity index (THI) was calculated to assess thermal stress severity. CYP1A2 expression was analyzed using Western blotting and immunohistochemistry (IHC), and these values were statistically compared with THI by Pearson’s correlation analysis. Results: The HS exhibited significantly higher THI values compared to the CON (88.11 vs. 66.67). Western blot analysis revealed significant upregulation of CYP1A2 expression in the HS compared to CON (1.89 vs. 1.00). IHC demonstrated that CYP1A2 was specifically localized in granulosa cells of mature follicles, with a significantly higher proportion of CYP1A2-positive follicles in the HS (15.92%) compared to CON (9.08%). When the obtained values were compared with THI values, CYP1A2 expression showed a strong positive correlation with THI (r = 0.41 and 0.74). Conclusions: This study revealed that heat stress can alter the ovarian microenvironment, including the expression of CYP1A2. These findings emphasize the need for effective thermal management strategies to mitigate heat stress-induced reproductive dysfunction in livestock production.
        4,000원
        6.
        2025.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 광체꽃벌속의 미기록종 Ceratina iwatai Yasumatsu, 1936을 한국에서 처음으로 보고한다. 본 종의 기재, 분포정보, 그리고 삽화를 제공한다.
        3,000원
        7.
        2025.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 논문은 라이소자임이 칸디다 알비칸스에 항균효능이 있음을 발견하였고 라이소자임의 분해 절편도 또한 항균효능이 있는지 단백질 분해 효소인 트립신을 처리하여 확인해 보았다. 130개의 아미노산 으로 구성된 14 kDa 단백질인 라이소자임을 약 24 kDa의 분자량을 가지는 단백질 분해 효소인 트립신으 로 분해 하였다. 분해된 생성물은 고성능 액체 크로마토그래피인 분석용 및 제조용 HPLC를 사용하여 분 석 및 분리하였다. 이를 통해 효율적인 라이소자임 소화를 위한 최적 조건을 확인하고, 분해된 펩타이드 절 편들을 분리하였다. 효능평가 결과, 일부 펩타이드 절편들이 칸디다 알비칸스에 강한 항균 활성을 보임을 확인하였으며 몇몇은 활성이 줄어드는 결과를 보였다.
        4,300원
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