• 한국수학교육학회지시리즈E:수학교육논문집
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• 제36권3호
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• pp.355-372
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• 2022

본 연구에서는 그릿 검사가 초등수학영재를 판별하는 도구로서 타당성에 대하여 검증하고자 하였다. 이를 위하여 문헌 연구를 통하여 선행 연구들에서 그릿 검사의 측정 도구들에 대한 자료를 수집하였고, 전문가 검토를 통하여 영재판별을 위한 판별 문항을 개발하였다. 본 연구를 위해 서울특별시 초등학교 일반학생 39명과 영재교육원 수학영재 20명을 대상으로 그릿 검사, 수학 문제해결력 검사, 수학 창의성 검사, 수학 행동 특성 검사를 실시하여 상관관계를 분석하였다. 상관관계 분석 결과 그릿 검사는 수학 문제해결력 검사와 0.521, 수학 창의성 검사와 .440, 수학 행동 특성 검사와 .601의 상관을 갖는 것으로 나타났으며, 모두 유의확률 p<.01 유의도를 보였다. 또한 판별 분석을 통하여 집단 판별의 유의성을 검증한 결과에서 그릿 검사는 집단 내 분산을 총 분산으로 나눈 Wilk's λ가 .799로 나타났으며 유의확률은 p<.001로 그릿 검사가 수학영재와 일반학생을 판별하는데 유의함을 확인하였다. 연구 결과, 그릿 검사가 초등수학영재를 판별하기 위한 대안적인 도구로 타당성이 검증되어 수학영재 판별 도구로 활용 가능할 수 있음을 나타낸다.

• Journal of Animal Science and Technology
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• 제64권1호
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• pp.70-83
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• 2022

A set of studies was performed to determine the influence of dietary ZnO concentration and source during two phases (days 0 to 14 and days 15 to 28). Experiment 1: 168 weaned piglets were allocated to four treatment groups in six replicates. The treatments included a basal diet without ZnO supplementation (control), 2,500 mg ZnO/kg (In2500), 500 mg nano-ZnO/kg (N500), and 150 mg nano-ZnO/kg (N150). Experiment 2: 168 weaned piglets were divided into three treatment groups with eight replicates. The treatments included control, In2500, N300, and 150 mg nano-ZnO/kg (N150). An in vitro trial showed that the growth of Listeria monocytogenes, Escherichia coli, and Salmonella typhimurium was inhibited when exposed to 300 and 500 ppm of ZnO after 24 h of incubation. In experiment 1, the average daily gain (ADG) by the pigs was improved in the N500 and IN2500 treatment groups. Colonization of coliforms and Clostridium spp. significantly decreased in the pigs fed the N500 and IN2500 diets in phase 1. The total plasma antioxidant capacity was greater in the IN2500 and N500 treatment groups than in the control. Superoxide dismutase (SOD) activity was greater in pigs fed the IN2500 (phase 1) or the IN2500 and N500 (phase 2) diets than in the control and N150 treatment group. In experiment 2, pigs in the N300 treatment group showed a higher ADG and lower fecal score colonization of coliforms and Clostridium spp. compared with those in the N150 treatment group. In conclusion, nano-ZnO at a dose of 300 ppm showed the same growth as the pharmacological dose of Zn. This provides an option to the pharmacological dose.

• Journal of Animal Science and Technology
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• 제64권1호
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• pp.84-96
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• 2022

The current study was conducted to evaluate the effect of calcium-enriched fatty acid supplementation on the growth performance, blood metabolites, intestinal morphology, carcass traits, and nutrient digestibility of broilers subjected to chronic heat stress. A total of 210 one-day-old broiler chicks (40.12 ± 0.25 g) were randomly allocated to one of five dietary treatments, to obtain six replicates per treatment. Broilers were subjected to chronic heat stress from day 21 to day 35, post-hatching, at 34℃ for 9 h per day. The body weight (BW) and feed intake of the experimental broilers were recorded weekly, and the average daily gain (ADG) and feed conversion ratio (FCR) were calculated accordingly. Rectal temperature was measured to compare the basal body temperatures between individuals, and blood samples were collected on days 21 and 35 to evaluate basal body temperature, serum total cholesterol, and the triglyceride content of the broilers. On days 21 and 35, one broiler from each cage (n=6) was euthanized to measure carcass trait parameters, nutrient digestibility in digesta, and intestinal morphology. On days 14, 28, and 35, the broilers fed 2.0% calcium-enriched fatty acids had higher BW (p < 0.05) than those fed the other diets. However, no differences (p > 0.05) were found in the average daily feed intake (ADFI) between dietary treatments over the 35 experimental days. On the other hand, on day 21, post-hatching, the broilers fed the 2.0% calcium-enriched fatty acid diet had improved (p < 0.05) dietary feed efficiencies compared to the other treatments. On day 28, the broilers fed the 5.0% of calcium-enriched fatty acid diet also had higher (p < 0.05) dietary feed efficiencies than those fed with the other dietary treatments. No effects (p > 0.05) on carcass weight, nutrient digestibility, intestinal morphology, or blood parameters were found between broilers fed with dietary treatments. This study demonstrated that the inclusion of an additive, containing 2.0% calcium-enriched fatty acid, to broiler diet could ameliorate the negative growth performance of broilers; and no interaction (p > 0.05) was observed between the calcium-enriched fatty acid and nutrient digestibility, digestive anatomy, blood metabolism, and carcass traits of broilers subjected to chronic heat stress conditions for 35 days post-hatching.

• Journal of Animal Science and Technology
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• 제64권1호
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• pp.1-9
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• 2022

Equilume light masks had no impact on hastening the resumption of estrous cyclicity in mares maintained in outdoor pastures on the mainland of Korea due to the cold weather conditions. Jeju Island is a major horse-breeding site in Korea and is warmer than the mainland during the winter season. Therefore, the primary objective of this study was to explore the efficiency of the Equilume light mask on the resumption of seasonal estrous cycles in Thoroughbred mares on Jeju Island. A total of 20 nonpregnant mares were randomly divided into the Equilume light mask (n = 9) and stable lighting (n =11) groups. The experiment was performed at seven different horse-breeding farms located on Jeju Island from November 15, 2020, to February 15, 2021. The mares were exposed to the respective lights from 16:00 to 23:00. Follicle size and uterine edema were measured by ultrasound scanning. Body condition scores (BCS) were also monitored during the experiment. Statistical analysis was conducted using the SAS and SPSS software, and p-values of < 0.05 were considered statistically significant. Two of the nine (22.2%) mares in the Equilume light mask group and three of the 11 (27.28%) mares in the stable lighting group were still cycling in December and January, which were considered as all-year-round cycling mares. On February 15, there was no difference between groups in the resumption of early seasonal estrus cycle, which was determined by follicles > 25 mm in addition to uterine edema. All mares in the Equilume light mask group and five of the eight mares (62.5%) in the stable lighting group had resumed cycling. Interestingly, six of the seven mares (87.5%) in the Equilume light mask and four of eight mares (50%) in the stable lighting group had already ovulated on February 15 (p > 0.05), as determined by the presence of a recent corpus luteum. No difference was observed in BCS and uterine edema between groups (p > 0.05). In conclusion, the Equilume light mask can be an effective approach to induce early seasonal estrus cycles of mares in Jeju Island, and it also enhances the efficiency of farm management by reducing labor.

• Journal of Animal Science and Technology
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• 제64권1호
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• pp.38-51
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• 2022

Whole-plant corn (Zea may L.) and sorghum-sudangrass hybrid [Sorghum bicolor (L.) Moench] are major summer crops that can be fed as direct-cut or silage. Proso millet is a short-season growing crop with distinct agronomic characteristics that can be productive in marginal lands. However, information is limited about the potential production, feed value, and ensilability of proso millet forage. We evaluated proso millet as a silage crop in comparison with conventional silage crops. Proso millet was sown on June 8 and harvested on September 5 at soft-dough stage. Corn and sorghum-sudangrass hybrid were planted on May 10 and harvested on September 10 at the half milk-line and soft-dough stages, respectively. The fermentation was evaluated at 1, 2, 3, 5, 10, 15, 20, 30, and 45 days after ensiling. Although forage yield of proso millet was lower than corn and sorghum-sudangrass hybrid, its relative feed value was greater than sorghum-sudangrass hybrid. Concentrations of dry matter (DM), crude protein, and water-soluble carbohydrate decreased commonly in the ensiling forage crops. The DM loss was greater in proso millet than those in corn and sorghum-sudangrass hybrid. The in vitro dry matter digestibility declined in the forage crops as fermentation progressed. In the early stages of fermentation, pH dropped rapidly, which was stabilized in the later stages. Compared to corn and sorghum-sudangrass hybrid, the concentration of ammonia-nitrogen was greater in proso millet. The count of lactic acid bacteria reached the maximum level on day 10, with the values of 6.96, 7.77, and 6.95 Log₁₀ CFU/g fresh weight for proso millet, corn, and sorghum-sudangrass hybrid, respectively. As ensiling progressed, the concentrations of lactic acid and acetic acid of the three crops increased and lactic acid proportion became higher in the order of sorghum-sudangrass hybrid, corn, and proso millet. Overall, the shorter, fast-growing proso millet comparing with corn and sorghum-sudangrass hybrid makes this forage crop an alternative option, particularly in areas where agricultural inputs are limited. However, additional research is needed to evaluate the efficacy of viable strategies such as chemical additives or microbial inoculants to minimize ammonia-nitrogen formation and DM loss during ensiling.

• Journal of Animal Science and Technology
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• 제64권3호
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• pp.481-499
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• 2022

This study aims to determine the effects of D-methionine (D-Met) isomer and the methionine precursor 2-hydroxy-4-methylthiobutanoic acid i (HMBi) supplementation on milk protein synthesis on immortalized bovine mammary epithelial cell (MAC-T). MAC-T cells were seeded using 10-cm dishes and cultured in Dulbecco's modified Eagle's medium/F12 (DMEM/F12) basic medium. The basic medium of DMEM/F12 was replaced with the lactogenic DMEM/ F12 differentiation medium when 90% of MAC-T cells reached confluency. The best dosage at 0.6 mM of D-Met and HMBi and incubation time at 72 h were used uniformly for all treatments. Each treatment was replicated six times wherein treatments were randomly assigned in a 6-well plate. Cell, medium, and total protein were determined using a bicinchoninic acid protein assay kit. Genes, proteomics and metabolomics analyses were also done to determine the mechanism of the milk protein synthesis pathway. Data were analyzed by two-way analysis of variance (ANOVA) with supplement type and plate as fixed effects. The least significant difference test was used to evaluate the differences among treatments. The HMBi treatment group had the highest beta-casein and S6 kinase beta-1 (S6K1) mRNA gene expression levels. HMBi and D-Met treatments have higher gene expressions compared to the control group. In terms of medium protein content, HMBi had a higher medium protein quantity than the control although not significantly different from the D-Met group. HMBi supplementation stimulated the production of eukaryotic translation initiation factor 3 subunit protein essential for protein translation initiation resulting in higher medium protein synthesis in the HMBi group than in the control group. The protein pathway analysis results showed that the D-Met group stimulated fructose-galactose metabolism, glycolysis pathway, phosphoinositide 3 kinase, and pyruvate metabolism. The HMBi group stimulated the pentose phosphate and glycolysis pathways. Metabolite analysis revealed that the D-Met treatment group increased seven metabolites and decreased uridine monophosphate (UMP) production. HMBi supplementation increased the production of three metabolites and decreased UMP and N-acetyl-L-glutamate production. Taken together, D-Met and HMBi supplementation are effective in stimulating milk protein synthesis in MAC-T cells by genes, proteins, and metabolites stimulation linked to milk protein synthesis.

• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2003년도 제27회 추계학술대회
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• pp.44-44
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• 2003

As a basic measurement tool in the areas of animal models of human disease, gene expression and therapy, and drug discovery and development, small animal PET imaging is being used increasingly. An ideal small animal PET should have high sensitivity and high and uniform resolution across the field of view to achieve high image quality. However, the combination of long narrow pixellated crystal array and small ring diameter of small animal PET leads to the degradation of spatial resolution for the source located at off center. This degradation of resolution can be improved by determining the depth of interaction (DOI) in the crystal and by taking into account the information in sorting the coincident events. Among a number of 001 identification schemes, dual layer phsowich detector has been widely investigated by many research groups due to its practicability and effectiveness on extracting DOI information. However, the effects of each crystal length composing dual layer phoswich detector on DOI measurements and image qualities were not fully characterized. In order to minimize the DOI effect, the length of each layer of phoswich detector should be optimized. The aim of this study was to perform simulations using a simulation tool, GATE to design the optimum lengths of crystals composing a dual layer phoswich detector. The simulated small PET system employed LSO front layer LuYAP back layer phoswich detector modules and the module consisted of 8${\times}$8 arrays of dual layer crystals with 2 mm ${\times}$ 2 mm sensitive area coupled to a Hamamatsu R7600 00 M64 PSPMT. Sensitivities and variation of radial resolutions were simulated by varying the length of LSO front layer from 0 to 10 mm while the total length (LSO + LuYAP) was fixed to 20 mm for 10 cm diameter ring scanner. The radial resolution uniformity was markedly improved by using DOI information. There existed the optimal lengths of crystal layers to minimize the variation of radial resolutions. In 10 cm ring scanner configuration, the radial resolution was kept below 3.4 mm over 8 cm FOV while the sensitivity was higher than 7.4% for LSO 5 mm : LuYAP 15 mm phoswich detector. In this study, the optimal length of dual layer phoswich detector was derived to achieve high and uniform radial resolution.

• Journal of Animal Science and Technology
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• 제64권2호
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• pp.380-395
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• 2022

This study investigated the utilization of detoxified Rhus verniciflua (RV) extract as a natural antioxidant to extend the shelf life of chicken breast meat during storage. Pre-heating at (35℃, 100℃, 120℃, and 140℃) was conducted on heartwood of RV prior to extraction to improve its antioxidant activity and remove the allergenic compound urushiol. The antioxidant activity was the highest when RV pre-heated at 120℃ with the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) scavenging activity observed at 62.29 EC₅₀ ㎍/mL and 12.11 IC₅₀ mg/mL, respectively. Pre-heating also significantly increased the total phenolic content (TPC), with the highest improvement was seen at 120℃, 100℃, and 140℃ respectively, wherein 35℃ shared no difference with the raw RV (RRV). Urushiol content was vanished following pre-heating at 120℃ and 140℃. With respect to these result, pre-heating treatment at 120℃ was applied before the extraction of the heartwood of RV. Prepared breast meat sample was dipped into distilled water as a negative control, 0.02% butylated hydroxytoluene (BHT) as positive control, and a solution containing detoxified RV extract (0.10%, 0.25%, 0.50%, 1.00%) at 4℃ for 60 min. Treatment group with 0.50% and 1.00% addition increased the redness and yellowness value on day 6 and day 3 of storage respectively (p < 0.05). The pH value of breast meat was also increased in treatment of 0.50% and 1.00% on day 0, but subsequently lower until end of storge day compared to control negative (p < 0.05). Furthermore, 0.50% treatment exhibited a higher antioxidant activity, stronger inhibition of the microbial growth evaluated by total viable count and maintaining a lower total volatile basic nitrogen among treatments (p < 0.05), unless for BHT and 1.00% treatment groups (p > 0.05). It indicates a similar efficacy of detoxified RV extract with that of positive control treated with BHT. The results of this study suggested that dipping chicken breast meat into a solution containing 0.50% of previously pre-heated RV heartwood at 120℃ could be a promising natural antioxidant for extending the shelf life, and at the same time improve its quality during storage.

• 한국엔터테인먼트산업학회논문지
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• 제13권8호
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• pp.515-524
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• 2019

본 연구는 2017년 청소년건강행태온라인조사의 원시자료를 이용하여 청소년의 스마트폰 사용량에 따른 주관적 건강 및 행복감, 신체활동과 정신건강에 미치는 영향을 알아보고자 하였다. 2017년(13차) 청소년건강행태온라인조사의 원시자료를 이용하였으며, 성별, 주관적 건강 및 행복감, 신체활동, 정신건강(주관적 스트레스, 우울감, 자살계획)으로 설정하였으며, 종속변수는 스마트폰 과사용 시간으로 하여, SPSS 22를 이용하여 각 변수에 대한 빈도분석과 로지스틱 회귀분석을 실시하였다. 분석 결과, 여학생은 남학생보다 스마트폰 과사용이 1.49배~1.67배 높았으며, 주관적으로 건강한 자는 그렇지 않은 자보다 1.2배~1.35배, 신체활동이 많은 자는 그렇지 않은 자보다 스마트폰 과사용이 1.17배~1.18배 높았다(p<.001). 반면, 주관적 행복감은 스마트폰 사용량을 예측하지 못했다. 또한 주관적 스트레스와 우울감이 있는 자는 없는 자에 비해 스마트폰 과사용이 각각 1.13배~1.22배, 그리고 1.37배~1.54배, 자살계획이 있는 자는 없는 자보다 스마트폰 과사용이 1.17배~1.24배 높았다(p<.001). 본 연구를 통해 스마트폰 과사용과 주관적 행복을 제외한 주관적 건강, 신체활동 및 정신건강의 연관성을 확인하였다.

• 한국심리학회지ㆍ건강
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• 제16권3호
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• pp.537-555
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• 2011

본 연구에서는 초등학교 4-6학년을 대상으로 첫째, 비만도에 따른 아동의 심리사회적 적응과 체력 수준의 차이를 밝히고, 둘째, 비만도와 체력이 과체중 이상 아동의 심리사회적 적응에 미치는 영향을 살펴보았다. 과체중 이상 아동은 '한국 비만 아동의 신체 활동과 건강(KOCPA)' 연구의 비만 캠프 프로그램에서, 대조군 아동은 서울 시내 초등학교에서 표준 성장도표의 체질량지수를 기준으로 모집되었다. 심리사회적 변인으로 자아 효능감 검사(식이 자아 효능감, 체중 조절 효능감, 신체 효능감), 자아개념검사, 소아용 삶의 질 검사가 사용되었으며, 신체 계측 및 체력은 직접 측정되었다. 연구 결과, 비만도가 증가할수록 심리사회적 적응과 체력 수준이 낮은 것으로 나타났다. 또한 과체중 및 비만 아동은 정상체중 대조군에 비해 유의하게 낮은 효능감 및 자아개념, 삶의 질을 보고하였다. 과체중 및 비만 아동을 대상으로 심리사회적 적응에 비만도와 체력, 두 변인의 상호작용이 미치는 영향을 알아본 결과, 체력이 좋을수록 높은 체중조절 효능감, 신체 효능감, 삶의 질이 예측되었다. 또한 비만도와 체력의 상호작용 효과가 비만 아동의 자아개념 수준을 예측하였는데, 이는 비만도가 그리 높지 않은 아동들은 체력 수준의 향상이 자아개념을 유지할 것이라고 예측 가능하지만 비만도가 상대적으로 매우 높을 경우에는 우선적으로 비만도의 감소가 우선적으로 이루어져야 함을 시사한다. 본 결과를 바탕으로 본 연구의 함의와 한계점에 대해 논의하였다.