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        검색결과 2,336

        1.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study aimed to investigate the relationship between the nutrition quotient and the dietary intake of adolescents. A total of 393 adolescents were surveyed to evaluate their Nutrition Quotient for Korean Adolescents (NQ-A) scores and dietary intake. The average age of the survey subjects was 15 years and the average NQ-A score of the subjects was 49.11±13.35. There was no significant difference in the NQ-A scores according to gender and age. The average dietary diversity score was 3.77±0.85, and it was significantly higher in boys than in girls (p< .05) with the scores of 12-14-year-old students being significantly higher than those aged 15-18 years (p< .01). The results of comparing the percentage of recommended intake or adequate intake and the mean adequacy ratio (MAR) according to the NQ-A grade, showed that the ‘High’ grade had a significantly higher intake percentage of vitamin B1, B12, folate, phosphorus, iron and a significantly higher MAR (p< .05). From a long-term perspective, efforts to improve dietary habits are deemed necessary to meet an individual’s nutritional requirements. Adolescents themselves should develop proper eating behaviors and acquire suitable dietary management skills to enhance their nutritional status, ultimately contributing to an improvement in their quality of life.
        4,200원
        2.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        최근 국내에서 개발된 송풍식 양파 줄기절단기를 수확기 양 파 엽 절단에 활용할 경우 적정 작업 조건을 구명하기 위해서 이 실험을 수행하였다. 처리구 중 식물체 엽 건조가 가장 많이 진행된(엽 건조 정도 : 66.3%, 엽 수분함량 : 50.5%) 6월 20일 엽 절단 처리구에서 평균 잔여 엽장은 6.7±3.5cm로서 작업 후 적정 잔여 엽장에 해당되는 범위인 4-10cm에 포함되므로 기계 엽 절단 성능이 처리구 중 가장 우수한 것으로 판단된다. 줄기절단기 이용 양파 엽 기계 절단 시 평균 작업 속도는 0.17m·s-1였는데, 이는 인력 엽 절단 처리구의 평균 작업 속도 인 0.05m·s-1보다 3.4배 정도 빨랐으며, 이를 통해 해당 기종 을 이용하여 10a 면적을 작업할 경우에는 인력 작업(1인 기준) 에 비해 2.6시간 정도를 절감할 수 있을 것으로 기대된다. 또한 기계 엽 절단 처리구에서의 손상구 발생률은 1.3%로서 인력 엽 절단 처리구의 0.0%에 비해 높았는데, 이로 인해 기계 엽 절단 처리구가 인력 엽 절단 처리구보다 저장 중 양파 구 부패 율이 평균적으로 높았던 것으로 판단된다. 처리별 저장 특성 을 살펴보면, 저장 8개월 후 구 부위(기부, 정부)별 부패율은 기계 엽 절단 후 잔여 엽장이 5.0cm 미만인 처리구에서 잔여 엽장이 5.0cm 이상인 처리구보다 높았다. 이는 잔여 엽 길이 가 5.0cm 미만인 처리구에서는 5.0cm 이상인 처리구보다 저 장 중 구 부패를 유발하는 병원균의 감염이 쉬우므로 장기 저 장 시 부패율이 높은 것으로 생각된다. 본 실험 결과와 실험 기 종의 성능 목표(작업 후 잔여 엽장 : 5cm) 및 양파 수확 시 적정 잔여 엽장에 관한 기존의 연구결과 등을 종합적으로 고려할 경우, 본 실험에 사용된 줄기절단기 이용 양파 엽 절단 시 양파 의 적정 잔여 엽장은 5-10cm 정도일 것으로 판단된다.
        4,000원
        3.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The research aimed to develop a high-efficiency plate-type heat exchanger for exhaust gas using computational fluid dynamics (CFD) thermal analysis based on the plate shape, and to identify the optimal shape. Following this, a water/air plate heat exchanger was manufactured, and its characteristics were studied experimentally. As the Re number increases on the gas (or air) side, the heat transfer rate increases significantly, whereas an increase in the Re number on the water side leads to a smaller increase in heat transfer. This is attributed to the larger convective heat resistance on the gas side, causing a substantial reduction in gas-side heat resistance as gas velocity increases, resulting in a considerable overall reduction in heat resistance. The fluid flow pressure drop showed similar results between the CFD calculations and experimental outcomes.
        4,000원
        4.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A checklist of dietary behavior items for the elderly was developed based on Korean dietary guidelines. First, a literature review was conducted, and 63 preliminary items, including 30 items on food intake, 12 on eating habits, and 21 on dietary culture, were obtained to evaluate the dietary guidelines. The preliminary items were evaluated by experts using Lawshe’s method to verify the content validity. They were then revised, resulting in 52 items: 25, 11, and 16 in the food intake, eating habits, and dietary culture domains, respectively. A face-to-face survey was conducted on 331 people over 65 years of age in the metropolitan area, and their one-day food intake was surveyed using a 24-hour recall method in August 2022. The 48 items, including 24, 11, and 13 items on food intake, eating habits, and dietary culture, respectively, correlated significantly with the evaluation indicators of nutrient intake, such as mean adequacy ratio, dietary diversity score, and nutrient intake density. These items were considered suitable for evaluating the elderly's compliance with dietary guidelines.
        5,100원
        5.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        To understand the spatiotemporal distribution pattern of zooplankton and the environmental factors influencing zooplankton abundance in Gomso Bay, major harvesting area of Manila clam (Venerupis philippinarum) in South Korea, zooplankton sampling was conducted four times in autumn (October 2022), winter (January 2023), early spring (March 2023), and spring (May 2023). Among the environmental factors of Gomso Bay, water temperature, chlorophyll a concentration (Chl-a), dissolved oxygen (DO), and pH observed different patterns, while salinity and suspended particulate matter (SPM) showed no significant statistical differences between the survey periods. The zooplankton in Gomso Bay occurred 33, 29, 27, and 29 taxonomic groups during each respective survey period. In October 2022 and May 2023, arthropod plankton were dominated, while in January and March 2023, protozoa were primarily dominant. Among the Arthropods, copepods including Acartia hongi, Paracalanus parvus s. l., Corycaeus spp., and Oithona spp. commonly found along Korean coastal areas of the Yellow Sea, were dominated. Cluster analysis based on zooplankton abundance indicated a single community (stable condition) in each season, attributed to low dissimilarity distances, while three distinct clusters (autumn, winter-early spring, spring) between seasons indicated a highly seasonal environment in Gomso Bay.
        4,800원
        6.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The levels of Indoor radon can increase in newly built apartments that mainly use construction materials such as concrete. However, radon measurement in newly built buildings has only been implemented recently, and there is a lack of sufficient data for radon management purposes. This study aimed to determine the levels of indoor radon in newly built apartments by regions, sizes of household, and floor (lower, middle, upper floor), and to explore the trend of radon reduction by time according to ventilation methods. Indoor radon was measured in 48 households in four regions (Gyeonggi-do and Gangwon-do). Measurements were performed for 48 hours and 24 hours under closed and ventilated conditions using real-time measurement devices FRD400 and RAD7, respectively. To analyze changes in radon concentration by floors, data were collected by dividing households into lower, middle, and upper floors according to their vertical height. The concentrations of indoor radon ranged from 12.1 Bq/m3 to 559.0 Bq/m3 when windows were closed and 12.0 Bq/m3~500.0 Bq/m3 when ventilated (including both mechanical and natural ventilation). On average, the concentration of closed conditions of household when sealed (arithmetic average 185.3 Bq/m3) was 1.5 times higher than the concentration during ventilation (including mechanical and natural ventilation: 123.8 Bq/m3), and around three times higher than the average for mechanical ventilation (65.7 Bq/m3). It was found that the indoor radon concentration statistically increased as the height increased and the size of the house became smaller. Typically, it took 7 to 8 hours to exceed the standard of 148 Bq/m3 after windows were closed. It decreased to less than 148 Bq/m3 within 3 to 4 hours after operating the mechanical ventilation system. However, in the case of natural ventilation, it takes more than 24 hours to reach below the standard value, and the concentrations stagnated after 24 hours. In conclusion, radon concentration in narrow spaces can be relatively high if ventilation is not sufficient due to the nature of apartments with wall-type structures. Therefore, it is necessary to prepare various radon reduction measures according to floor, size, and ventilation methods.
        4,000원
        7.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 낙지의 생식생태 이해에 필요한 수컷 생식기관과 정포의 미세해부학적 구조를 기재 하였다. 낙지는 교접완의 유무를 통하여 성을 구별할 수 있는 성적이형을 갖는 종이다. 수컷 생 식기관은 정소, 일차수정관, 저정낭, 이차수정관, 정포선, 정포낭으로 구성된다. 정소는 조직학 적으로 정세관형이었으며, 수컷 생식세포들은 층상배열상을 보였다. 일차수정관은 정소와 저정 낭을 연결하는 관으로 상피층과 결합조직으로 이루어져 있었다. 저정낭은 일차수정관과 이차 수정관의 사이에 위치하며, 상피층은 상피세포와 점액세포로 구성된다. 점액세포는 AB-PAS (pH 2.5) 반응에서 푸른색, AF-AB (pH 2.5) 반응에서 보라색으로 반응하였다. 이차수정관은 저정낭 과 정포선을 연결하는 짧은 관으로 내강에 주름이 발달하였다. 정포선은 다수의 관상선으로 이루어져 있었으며, 분비세포는 호산성 과립을 가지고 있었다. 정포낭은 주머니 모양으로 내강 에 주름이 발달하였으며, 상피층에 공포상의 분비세포가 존재하였다. 정포는 길이 약 83.5 mm 로 전방부의 당김사, 중간부의 발사체와 고정체, 후방부의 정자 저장부로 구성되어 있었다.
        4,000원
        8.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        우리나라 여러 해양환경 지역으로부터 확보한 370주의 해양세균, 균류, 미세조류로부터 기초생 리활성(항산화, 항염, 항균, 항암, 항바이러스)을 조사하여 채집지, 분리원, 종(種) 수준에서의 활성결과를 비교하였다. 해양세균의 경우, 일반적으로 유용성이 많이 알려진 Streptomyces 속 과 Bacillus 속에 속하는 균주들이 두드러진 강한 효능이 관찰되었고, 주로 해양퇴적물로부터 유용한 자원을 분리할 수 있었다. 해양균류와 미세조류의 경우에도 종 특이적으로 활성이 강 하게 나타나는 결과를 확인할 수 있었고, 효능 특이적으로 활성을 보이는 결과도 얻을 수 있었 다. 이러한 결과를 바탕으로 추후 특정질병에 선택적으로 효능을 보이는 화학물질 연구 또는 자원 기반 연구 수행 시 유용성을 전제로 한 자원 확보 전략 수립과 산업 활성화를 위한 전 략소재로 우선적 접근이 용이할 수 있는 연구결과라 생각된다. 또한, 이들 결과를 해양바이오 뱅크를 통한 분양소재로 활용함으로써 학계, 산업계에서 활용하여 해양바이오산업 활성화에 좀 더 빠른 접근을 도울 수 있다고 생각한다.
        4,600원
        9.
        2023.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        To develop a functional probiotic that inhibits gingipain, a major virulence factor of Porphyromonas gingivlais (P. gingivalis), we screened over 30 probiotic strains for their ability to inhibit gingipian activity. We investigated the inhibition of expression of gingipain genes kgp, rgpA, and rgpB as well as gingipain activity, using freeze dried cell-free supernatants of Weisiella cibaria SPM402 (WC402) and Lactobacillus paracasei SMP412 (LP412), both of which demonstrated antibacterial activity against P. gingivalis. Thus, it was verified that kgp expression was reduced by approximately 0.71±0.02 folds and rgpB expression was reduced by approximately 0.71±0.14 folds at a concentration of WC402 10 mg/mL. Meanwhile, at the same concentration of 10 mg/mL of LP412, kgp expression was reduced by approximately 0.19±0.08 folds, rgpA expression was reduced by approximately 0.09±0.02 folds, and rgpB expression was reduced by approximately 0.24±0.03 folds. At a concentration of 10 mg/mL, Kgp activity was inhibited by approximately 78.65±3.58% (cell associated gingipain, CAG), 82.45±1.22% (cell-free gingipain, CFG) by WC402 and 80.71±2.11% (CAG), and 85.81±0.05% (CFG) by LP412 respectively. Rgp activity was also effectively inhibited by approximately 78.6±1.01% (CAG), 86.78±0.47% (CFG) and 82.93±1.26% (CAG), 88.81±0.36% (CFG) by WC402 and LP412 respectively. Based on these results, W. cibaria SPM402 and L. paracasei SPM412 can be regarded as functional probiotics with the ability to inhibit gingipain activity and exhibit antibacterial effects against P. gingivalis.
        4,000원
        10.
        2023.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        To investigate residual pesticide levels in agricultural products contained in Meal-kits, 27 Meal-kit products were collected from marts, Meal-kit shops, and online stores in Incheon City, South Korea. Seventy-six vegetable and thirty-seven mushroom products were analyzed for residual levels of 339 pesticides. Residual pesticides were detected in 23 out of 76 vegetables and were not present in the 37 mushroom products. The residual pesticide detection rate was 20.4% (23/ 113 cases). The pesticides famoxadone 0.034 mg/kg (standard: 0.01 mg/kg or less, PLS) and fenpyroximate 0.302 mg/kg (standard: 0.01 mg/kg or less, PLS) exceeded their maximum residue levels (MRL). This survey revealed that various types of pesticides remain in agricultural products in Meal-kits. Due to the nature of Meal-kit products, there is no separate standard for residual pesticides in agricultural products. Therefore, continuous monitoring of residual pesticides is necessary.
        4,000원
        13.
        2023.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, the structural performance of the specimen fabricated through 3D printing was evaluated through monotonic loading experiments analysis to apply to 3D printed structures. The compression and flexural experiments were carried out, and the experimental results were compared to the finite element model results. The loading directions of specimens were investigated to consider the capacity of specimens with different curing periods, such as 7 and 28 days. As a result, the strength tended to increase slightly depending on the stacking direction. Also, between the 3D-printed panel composite and the non-reinforced panel, the bending performance depended on the presence or absence of composite reinforcement.
        4,000원
        14.
        2023.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        This study used optical and scanning electron microscopy to analyze the surface oxidation phenomenon that accompanies a γ'-precipitate free zone in a directional solidified CM247LC high temperature creep specimen. Surface oxidation occurs on nickel-based superalloy gas turbine blades due to high temperature during use. Among the superalloy components, Al and Cr are greatly affected by diffusion and movement, and Al is a major component of the surface oxidation products. This out-diffusion of Al was accompanied by γ' (Ni3Al) deficiency in the matrix, and formed a γ'-precipitate free zone at the boundary of the surface oxide layer. Among the components of CM247LC, Cr and Al related to surface oxidation consist of 8 % and 5.6 %, respectively. When Al, the main component of the γ' precipitation phase, diffused out to the surface, a high content of Cr was observed in these PFZs. This is because the PFZ is made of a high Cr γ phase. Surface oxidation of DS CM247LC was observed in high temperature creep specimens, and γ'-rafting occurred due to stress applied to the creep specimens. However, the stress states applied to the grip and gauge length of the creep specimen were different, and accordingly, different γ'-rafting patterns were observed. Such surface oxidation and PFZ and γ'-rafting are shown to affect CM247LC creep lifetime. Mapping the microstructure and composition of major components such as Al and Cr and their role in surface oxidation, revealed in this study, will be utilized in the development of alloys to improve creep life.
        4,000원
        15.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The effects of exogenous sodium nitroprusside (SNP, nitric oxide donor) on the growth, yield, photosynthetic characteristics, and antioxidant enzyme activity of kimchi cabbage (Brassica rapa L. subsp. pekinensis (Lour.) Hanelt) was studied under the low temperature conditions. Kimchi cabbages were treated with SNP of three concentrations (7.5, 15, 30 mg·L-1) for three times at four-day intervals and exposed to low temperature (16/7°C) stress for seven days. SNP treatment induced increases of net photosynthetic rate (Pn), stomatal conductance (Gs), intracellular CO2 concentration (Ci) and transpiration rate (Tr) under the stress condition with the highest level after the third treatment. The contents of malondialdehyde (MDA) and H2O2 were significantly lower in the treatment of SNP compared to the non-treated control. The activity of ascorbate peroxidase (APX), catalase (CAT), peroxidase (POD) and superoxide dismutase (SOD), increased in treated plants by up to 38, 187, 24 and 175%, respectively compared to the non-treated control. SNP-treated and untreated plants had similar growth characteristics. Compared to the control group, SNP-treatment increased fresh weight and leaf area by 5%. Overall, our findings suggest that the application of sodium nitroprusside to the leaves contributes to reducing physiological damage and enhancing the activities of antioxidant enzymes, thereby improving low temperature stress tolerance in kimchi cabbage.
        4,000원
        16.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        ITO 투명 전극 필름은 디스플레이, 전기 자동차 등 산업 전 범위에서 널리 사용되는 전자 재료이다. 본 연구에서는 이러한 indium tin oxide (ITO) 필름의 열성형 안정성을 향상시키기 위하여 Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) 전도성 고분자 코팅 용액 조성을 결정하였다. 1000 S/cm의 고 전도성을 보이는 PEDOT:PSS 용액에 끓는점이 각기 다른 4가지 종류의 용매를 희석하였고, 코팅 전 후 면저항 변화를 분석하였다. 또한 380~800 nm 영역의 광 투과율 분 석 및 Raman 스펙트럼 분석을 통하여 PEDOT:PSS 박막이 코팅된 ITO 투명 전극의 전기적 특성 결정 메커니즘을 규명하였 다. 230°C 열성형 공정 결과 ITO 필름은 113% 연신 상태에서 이미 전기 전도성을 읽었지만, ethylene glycol을 희석 용매로 사용하여 얻어진 전도성 고분자 박막이 적용된 ITO 필름은 126% 고 연신 상태에서도 초기 60 Ω/sq 면저항을 246 Ω/sq로 유지하는 우수한 전기 전도성을 보였다.
        4,000원
        17.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        산업과 기술의 발전으로 인해 수계로의 화학물질 배출이 증가하고, 이로 인해 환경오염과 인체 건강에 부정적인 영향을 미치 는 위험이 더욱 증가하였다. 따라서, 수질을 종합적으로 평가할 수 있는 생태독성평가의 중요성이 강조되고 있다. 본 연구에서는 렌즈프 리 그림자 이미징 기술을 활용한 Cellytics 플랫폼을 소개하며, 화학물질에 의한 로티퍼(Brachionus plicatilis)와 미세조류(Dunaliella tertiolecta) 의 생물학적 변화를 신속하게 측정하고 독성을 분석하는 기법을 제안한다. 이를 위해 로티퍼와 미세조류를 톨루엔에 각각 1분과 5분 동 안 노출한 뒤, Cellytics를 이용하여 로티퍼의 이동성과 미세조류의 형태 변화를 측정하여 독성을 평가하였다. 로티퍼의 이동성과 미세조류 의 형태변화는 모두 110.4 mg/L의 농도에서 대조군과 유의미한 차이를 나타내며(p<0.05), 이는 로티퍼의 생존율로 분석한 톨루엔의 LC50(552 mg/L)보다 낮은 농도였다. 본 연구에 따르면, 로티퍼와 미세조류를 전통적인 방식으로 최소 수 일 간 배양하여 얻을 수 있는 생 태독성평가 결과를 매우 짧은 시간(5분 이내)에 분석하고, 두 생물의 독성평가 결과를 신속하게 제공하여 현장에서 활용 가능한 신뢰성 높은 정보를 제공할 수 있음을 보여준다. 이는 독성평가를 이용하는 다양한 연구의 활용에 기여할 수 있으며, 환경보호 및 인체 건강 관 련 정책 수립에 도움이 될 것으로 기대된다.
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